KWB 1/2" Grade 100 Master Link Sub Assembly w/ Shorteners - 3 & 4 LegKWB 1 2" Master Link Sub Assembly with Built In Shorteners 3 & 4 Leg, Grade 100 The KWB 1 2" Master Link Sub Assembly is engineered for heavy duty 3 and 4 leg Grade 100 chain sling configurations. With a 39,000 lb. working load limit and integrated chain shorteners, this assembly allows riggers to adjust sling length efficiently without the added bulk of separate grab hooks or excess chain. Multi Leg Adjustability Without Extra Hardware Built for 1 2"