Why is there a hole in the splicer pin?

The hole in the splicer pin on Coolubricator^™ nozzles allows for a small amount of fluid to be mixed upstream of the nozzle tip, which helps maintain a consistent fluid output between pump strokes. Coolubricator^™ nozzles use a splicer with a hole in it. Serv-O-Spray^™ nozzles use a splicer with no hole in it.

Related video:

Unist - How To: Working With The Redesigned Capillary Splicer