Will these work with my truck if I'm jumping a smaller car?

Yes. The 600 amp rating covers both directions—truck-to-car or car-to-truck. Just connect positive to positive, negative to negative, and start the donor vehicle first.

Are the clamps solid or do they have insulated handles?

The cable set includes clamps at both ends; clamp construction details aren't specified. Test the grip and jaw closure before your first jump to make sure they seat firmly on terminals.

Can I leave these coiled in my trunk year-round?

Copper wire is tough, but coiling them loosely and storing in a dry spot extends life. Tight coils under heat can degrade insulation over time—unwind them every few months if they're sitting.