Our 28-11 extension ladder step locking kit is suitable for aluminum extension ladder D1200-2 and D1300-2 series ladders. The aluminum extended is made of high-quality aluminum alloy, which is sturdy, damage , and has a long service life. Even after collision and wear, it can provide solid support. The extended can be used for applications, suitable for indoor and outdoor use. Easy to install: You only need to remove old or step locks and install our aluminum rung locks. If your old lock design is different from this lock. You may need to locate measures and mark them, and drill holes. Our extended kit includes 4 ladder locks, 16 washers -1, 16 nuts, and 16 washers -2. You do not need to purchase other installation parts, which provides great convenience for maintenance of your extension ladder. Colour:As Shown Material:Aluminum alloy Package Contents: 4 x Extension Ladder Accessories Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.