Check the listing for details. Wilson Combat 1911 Commander 4.25" Recoil Spring 17lb - 10C17. Condition: New. Listed at 12.95 USD. Wilson Combat Recoil Spring Model: 10C17 Weight: 17 LB Fits: Commander 4.25" 1911 Brand new & factory sealed Product Description: Recommended Use: Commander-Size 4.25" .45 ACP shooting 185 gr. / 200 gr. standard pressure target or standard pressure JHP self-defense ammunition with a power factor of 160,000 to 175,000 (Velocity x Bullet Weight = Power Factor) Average Service Life: 2,000 Rounds Wilson Combat Heavy-Duty Recoil Springs are made combat tough to repeatedly take a pounding yet show remarkably consistent performance every time a round is fired. Keeping a fresh recoil spring in your pistol will dramatically reduce the pounding your slide and frame receive. HOW TO TEST TO MAKE SURE YOU HAVE THE CORRECT RECOIL SPRING WEIGHT FOR YOUR AMMUNITION: Go to the range with your pistol and a magazine that will positively lock your slide to the rear when you slowly retract the slide with the pistol empty. Load one round of the desired ammunition in the proven magazine, load the pistol and fire the single shot holding the pistol in your strong hand, but grip the pistol fairly loose. If the pistol consistently (5 to 10 shots is adequate) locks the slide to the rear, the recoil spring is not too heavy for your ammunition. A recoil spring that is 1-2# below the weight where you begin to have failures to lock open is ideal for your ammunition. Payment: We handle all payments through Paypal. Please pay at the time of purchase so we can ship out your item to you as soon as possible. Shipping: We ship all items via USPS. Most orders are shipped within 24 hours. Delivery time in the US is normally between 2-5 business days. Terms: We accept returns for refunds within 30 days of delivery date on unopened packages only. Return shipping paid for by buyer. We will be happy to issue a refund/exchange if a buyer receives a product that is not as described. Thank you for looking and please contact us with any and all questions!