Optional strap extension kit provides an additional 5 inches of adjustment for our 30-0083 XLR Dual Head Mirror and our 30-0086 XLR 2.5 Tow Mirror. This extension kit will allow you to fit many oversize mirrors. This kit is not available in stores at this time. Please call us at 800-327-7463 or 562-531-1395 to place an order. Cost for one set to fit one mirror is $7.00 plus postage.