Use/NoteVertical=unlock; Horizontal=lock; Left truck T-lock=rotate counterclockwise 90 degree to lock on & reverse operation unlocking; Right truck T-lock=rotate clockwise 90 degree to lock on & reverse operation unlocking.MaterialThe truck topper t-handle lock is made of Zinc die cast with black powder coating finish, ensure long lasting in outdoor environment.Dimension The truck cap lock rod is 1-11/16 length, install screw bolt 1/2 length, locking cam 2-3/4 length, other details dimension and install opening size as image-3. Recommend check the size is fit your truck cap before purchase.Package includes: 1* Left Cap T-lock, 2*keys, 2*installing bolts, 1*locking cam, 1*cam fix bolts.Easy to InstallBase on the L/R label or lock/unlock by yourself test to identify L/R lock at first; 2nd insert the truck camper t-lock rod through the install hole, adjust the hole size if needed; 3rd security the install screws to ensure cap t-locks firmly fixed on the truck camper door, then install the locking cam correctly and tighten the screws.