Ball Bearing Fiddle Block with Becket 706-55Fiddle block with anodized aluminum cheeks, becket and ball bearing sheaves. Works with 706 45 for a 4: 1 purchase. Delrin(tm) ball bearing sheaves feature a single top sheave and two in line sheaves to spread the load reducing friction and chafe. Swivel head design may be locked in place to avoid twist. Upper Sheave Dia. 2 3 8" (60mm), Lower sheaves diameter 1 13 16" (46mm), Sheave Dia. 2 3 8" (60mm), Thickness 1 3 32" (28mm), Width 3 31 32" (101mm),