Although the Kimberwick resembles a snaffle, the bit mouthpiece is not centered on the ring. It is used with a curb chain, thus the ring acts like a bit shank and creates leverage, making it a type of curb/Pelham bit.

Uxeter Kimberwicks (the ring has slots to place the reins in a specific location) Which slot used determines poll pressure. The upper slot, products less poll pressure than rein attached to the lower slot. By adjusting poll pressure you are adjusting head lowering effect. Unslotted Kimberwicks due to curb chain give more control than a snaffle.