Through the years Ive had several questions about the resource of the California Ported Snaffle. The bit is absolutely one of my favorite resources in getting a young horse to confidently accept the bit.
Interesting, it was brought to me many years ago. It seems that it was never commercially made. The old time Californio Horsemen would take a mouth piece, remove shanks and build in the slip to help a horse with the bitting process. The slip helps the horse learn he can pick the bit up to remove pressure off his lips, tongue and bars. The cricket allows a horse to roll his tongue and at the same time relax his jaw. A relaxed jaw helps a horse relax his entire body.
It's a good bit to start the bitting process taking a horse from ring snaffle into a bridle. The first ride or two it might feel stiff but just bend around a little bit let the horse get used to it. The curb and rein goes in the O ring. Since it does not have any shank it does not have any curb pressure but needs a leather hobble strap just so you don’t pull the bit through the horses mouth.
The California Ported Snaffle offers direct control like an O-Ring snaffle while introducing the opportunity for a horse to carry something solid in his mouth versus the broken snaffle. Depending on the height of the horses pallet one might get a little pressure at the roof of the horses mouth. 
A reminder this is not a bit for use in competition. Its job is to prepare a horse for the bits he will have the opportunity to carry in his career. I'm including a couple photos for your visual, note the leather hobble strap. Though Reinsman has discontinued this bit in the Camarillo line, it is still available at in my store here at www.sharoncamarillo.com. It is the California Ported Snaffle, #708.
Let me know how you get along.
Good luck, Sharon