Models with conventional shackle (with rear spring eye); Single leaf with safety wrap or two leaf. 12,000 Lb and 13,300 Lb GAWR only. Half leaf is for safety in case of eye failure; Only on front end of spring. These spring groups (1 1/2 and 2 leaf) are identical except for capacity, bushings and wedge. Except where noted all springs have 2 1/4" eyes. Except where noted all springs using RNK bushings have reducing sleeves for the bushings. Most vehicles built after 7/31/2012 use the 2 leaf springs.