These Selden blocks are optimised for wires or Dyneema/Spectra core.
Stainless steel, electro polished cheeks, anodised aluminium sheave and polymer plain bearing bushing.
Outer side plates to increase breaking load – but still optimising the weight.
The sheave is V-shaped for wires.
Light holes to reduce weight.
Two polyamide washers on pin/bushing to reduce play between wire terminal and cheeks.
Designed for wire applications subject to rig loads, e.g. backstays.