Expensive but worth it
"While gut is expensive I have found that it holds tension better and longer. Allowing more playing days between string jobs so the cost difference is not as great as it seems. Also it’s much easier on the arm and shoulder."
Wilson
WRZ999:SET
The all new Wilson Natural Gut gets an upgrade in more ways than one. Now with an even better price and a slightly firmer feel these strings still remain the Rolls Royce of the tennis string market. Although the strings are slightly firmer, don't fret as they are still exceptionally comfortable and perfect for players with arm issues. Made from cow intestines, this string takes significant time and resources to produce, providing players with the utmost in feel and playability. Great by itself or in a hybrid application, Wilson Natural Gut features a moisture resistant, long-life coating to protect your investment.
Composition: Natural Serosa Fibers
Gauge: 16G (1.30 mm), 17G (1.25 mm)
Length: 40 ft (12.2 m)
For more information on strings, see our following blog posts:
The Future is Hybrids: Top Hybrid String Choices
Breaking Down the 4 Main Types of String
String and Tension Tips from Tennis Express Stringing Experts
For more information about choosing a tennis string, click here.
Any original shipping fees are none refundable.

| From | To | Standard Ground* | 2Day | Next Day | |
|---|---|---|---|---|---|
| $0.00 | $49.99 | = | $5.95 | $15.95 | $29.95 |
| $50.00 | $149.99 | = | Free | $15.95 | $34.95 |
| $150.00 | $199.99 | = | Free | $19.95 | $39.95 |
| $200.00 | $9,999.99 | = | Free | $19.95 | $39.95 |
| From | To | USPS Priority* | |
|---|---|---|---|
| $0.00 | $99.99 | = | $19.95 |
| $100.00 | $199.99 | = | $39.95 |
| $200.00 | $9,999.99 | = | $49.95 |
Orders being shipped outside of the Contiguous US or APO addresses will ship by means of the United States Postal Service (USPS) and in some cases FedEx.
**Shipping via USPS Priority provides minimal tracking information and normally delivers within 5-7 business days.
*** Any shipping promotions offered by Tennis Express DOES NOT apply to shipments outside of the contiguous 48 states.
**** Excludes tennis balls, court equipment, stringing machines, ball machines and all oversized items.
At this time, Tennis Express only ships to the United States and all US Territories including Puerto Rico, US Virgin Islands, Guam and military bases. Due to manufacturer restrictions, we are unable to ship to countries outside of the United States.
Return Policy
Tennis Express believes in providing our customers with the best selection of tennis products and innovative game improvement gear. If the products are not to your liking, please take comfort in knowing you can return or exchange unused products within 30 days of the delivery date. Used or worn product is ineligible for a Refund. However, Tennis Express may issue a partial store credit for product returned in a used or worn condition. Credit is at the discretion of Tennis Express based on the amount of wear and use on the product. Store credits expire after 90 days.
How to Return
Submit a return request by visiting Return Portal.
1. Log in with your order number and email.
2. If your order has more than one item, select the items that you want to return.
3. Select the item condition and reason for return. Optionally add any comments.
4. Save and continue to return options.
Once your return request is approved, you'll receive an email with a label or QR code for your FedEx return label and shipping instructions. After the product is returned, you receive a refund.
To qualify for a FREE prepaid FedEx Ground return label:
* Your order must be over $50 (before tax and any shipping fees).
* After your return, the value of what you keep must still be over $50 (before tax and any shipping fees).
* Limit 1 free return label per order.
* Valid only for the continental United States.
Example: You place a $75 order and return a $30 item. Your remaining total is $45, which is under $50, so this order does NOT qualify for free return shipping.
If your order does not qualify for free return shipping, you can still use our return portal for a flat $6.95 fee, which will be deducted from your refund. Otherwise, you're responsible for shipping items back to us, so please hold onto your tracking information.
Please note:
* If you use one of our prepaid labels, you may drop the shipment off at any authorized FedEx or USPS Service Station.
* Refunds will be processed within 3-5 business days from the day we receive the return.
* Any original shipping fees are non-refundable.
* Any store credit issued will expire within 90 days.
QUESTIONS: If you have any questions about our return process, please contact us before shipping back your return: [email protected]
Apparel Returns and Exchanges
* Apparel must be unworn, unwashed, and unused with original tags attached.
* For safety concerns, we cannot accept used or washed clothing.
* Accessories must be unworn, unwashed, and unused with original tags attached.
* Apparel items carry NO warranty from the manufacturer.
Shoe Returns and Exchanges
* Shoes must be in NEW and unworn condition with original product packaging.
* DO NOT use the original shoe box as the outer shipping box. This will ruin the product.
* Accessories must be unworn, unwashed, and unused with original tags attached.
* For shoe outsole warranty claims, please visit our Shoe Warranty page.
Final Sale Notice: All Clearance Shoes and Apparel are Final Sale and not eligible for returns or exchanges.
Racquet and Paddle Returns and Exchanges
* Racquets or Paddles must be in NEW and unused condition with original plastic covering the handle intact.
* Make sure any racquets or paddles are protected to safely endure shipment.
* For racquets strung at Tennis Express, the cost of the string will not be refunded.
* All sales are final on the purchase of used racquets.
* For racquet warranty claims, please visit our Racquet Warranty webpage.
Drop Ship Returns
* Items shipped directly from the manufacturer must be returned to the manufacturer within 30 days of the original delivery date.
* You must request a Return Authorization (RA) from Tennis Express prior to shipping. Please email [email protected] with your return request.
* Drop shipped items must be in new and unused condition with original product packaging.
* Any restocking fees or return shipping costs will be paid for by the customer.
Damages and Issues
Please inspect your order upon reception and contact us immediately if the item is defective or damaged, or if you receive the wrong item, so that we can evaluate the issue and make it right.
Unfortunately, we cannot accept returns on gift cards.
Last Updated 05/07/26
Overall rating: 5.0 / 5 from 8 reviews.
Review topics: ["power","gut","string"].
"While gut is expensive I have found that it holds tension better and longer. Allowing more playing days between string jobs so the cost difference is not as great as it seems. Also it’s much easier on the arm and shoulder."
"It’s good, solid natural gut."
"The Wilson natural gut is so playable. You get this wonderful "ping" with each shot and the control is unbelievable. I've hit with rackets that aren't stringed with natural gut (including the "synthetic" gut and other what I believe to be nylon based strings and it's like hitting with a paddle or a board. No feel, no touch. I've used natural gut strings for 50 years and can only remember a small handful of times I broke one. I'll usually replace thenm when they get frayed, but that's after playing with the gut strings for a couple of years. Yes, I get at least 2 years of use out of practically every gut string I've ever had my rackets strung with."
"Not mone"
"Im a 3. 5 player/team captain always looking to improve my game. Ive tried various nylon/poly hybrid string setups before, but with my recent switch to an AeroPro they were too hard on the elbow. I came across an article on Nishikori that detailed his strings: Wilson Natural Gut and Luxilon 4G 125mm. I strung it at 56 and have been amazed at the pocketing and control. It still has plenty of power and yet is very easy on the arm. I love this combo."
"Best strings Ive ever used so far!"
"Tennis Express is most dependable. I order everything, has to do with tennis, from it."
"I have played with Gut strings couple of times before but the Wilson ones seems a bit different. These seemed softer and I have no problem directing the ball all over the court. Nice power to hit the deep corners and I have been able to keep my opponents at the baseline. Drop shots and net plays are deadly and almost an unfair advantage. I strung these up myself and I waxed the mains before installing the crosses. Not sure if it helps or not but its been a month and the strings are holding up nicely. I do notice some string frays but I believe this is normal characteristics of natural guts."