For racers, there's no better adjustable genoa car system than one by Harken. A slider car system is a good choice for racing applications because it allows fast adjustments in varying environments. For example, you can use Harken Slider Genoa Lead Cars
for genoa and carpi leads in environments requiring constant changing of positions. These lead cars run on a ball bearing track and have 60-degree pivoting sheaves for easy trimming. The result is the ability to take advantage of changing wind and sea conditions immediately to keep the vessel moving at high speeds. They also allow you to work closely with the crew to help trim up the boat when the helm is overpowered.
Cruisers won't need quite as much versatility in terms of positions, so a pinstop genoa lead is typically adequate. In fact, any sailing application where lead positions change infrequently will be better suited for a pinstop style. Pinstop type leads can only be adjusted on the unloaded side of your boat, meaning you won't be able to adjust the genoa unless you tack. Harken Pinstop Jib Leads
are a good choice for such applications, as they feature a spring-loaded pinstop with precise track spacing and a removable bar for attaching a spring and block. This size is most appropriate for smaller boats (up to 27 feet long).