3/8-16, 15/16In. stud length, approx. 1-5/8" overall lenght. You need the extra 1/2" length to ensure full clamping and thread engagement.
If you use an accessory lug, jumper post, or thicker cables, dual battery etc, you may need this longer bolt versus the normal.
If you use the shorter bolt in a location requiring more length, you might not get full thread engagement: risk of poor connection, or the clamp may bottom out before tightening properly.
Fits many older chevy full-size 1992-2002 era large trucks and SUVs like Blazer C1500 C2500 C3500 K1500 K2500 K3500 Suburban Tahoe Yukon.
Measure your old bolt: from underside of the head to tip. Compare it to spec ~1-1/8″ vs ~1-5/8″. Also measure how far the clamp reaches past the post and whether there are spacers or stacked lugs — if so, you may need the longer bolt. If your old bolt is short (around 1-1/8″) and there are no extra lugs/spacers, go with the shorter for a cleaner fit.