Adjusts From 4-1/8" To 7" To Fit Thickness Of Wall. No. 3Rv-Wt: Size: 3", A = 3-5/8", B = 10-5/8" No. 4Rv-Wt: Size: 4", A = 4-5/8", B = 10-5/8" No. 5Rv-Wt: Size: 5", A = 5-5/8", B = 10-5/8" No. 6Rv-Wt: Size: 6", A = 6-5/8", B = 10-5/8"