Tim, the best I could find was a picture of one on the 6066gmcguy web site, about the middle of the page. A google search tuned up a bunch of modern cars that use them but nothing about the type and the turn on pressure. You might be able to contact Jolly and find out the application of the one he used.

"It's just a phase. He'll grow out of it." Mama, 1964

1956 Chevy 1/2-ton 3100
1953 Chevy 6100 "The Yard dog"
1954 GMC Suburban Now with a new proud owner.