Single 12 Series Block with becket and UC Ball bearing sheave. Powerful 4" (102mm) sheave diameter runs on Nomex(tm)/Teflon(tm) composite bearing and twin ball bearing races for maximum thrust load capacity. Stainless Steel cheeks are reinforced for high loads. Swivel head "D" Shackle may be locked in place. Bolted construction allows for disassembly and proper maintainence. Removable becket allows for the use of pre-spliced line. Sheave Dia. 4" (102mm), Thickness 1 1/2" (38mm), Width 4" (102mm), Length 9 25/32" (248mm), SWL 5000 lbs (2270kg), Weight 3lbs 1oz (1.39kg), Max Line 3/4" (19mm)