I used a friends Cocker with this drop on it. The drop and his 20oz were a perfect combo. Tucked in the tank very nicely. However, when I let him use my palmer there was only about 1/2 cm of room between the bottem of the reg and the drop. Made adjusting the reg hard. It however is sturdy and a quality piece of equipment.
Great the the price gets the job done well. Also has offset holes for spyders. Maybe too bug for some.