Stand up spring block with Stainless Steel cheeks.  Square base matches Schaefer 3 series stand up blocks built in the 1970's and 80's.  Delrin(tm) sheave ensures smooth operation and high safe working load.  Sheave Dia.1-7/16" (37 mm), Max Line 7/16" (11 mm), Base width 1-3/4" (44mm), Height 3-17/32" (89 mm), Bearing Height 2" (51 mm), Fastener Size (4), #10 RH (5 mm), C/C 1-1/16" (26 mm), SWL 1000lbs (450 kg), Weight Stain. 3.5 oz (99 g)