I carry three or 4 different diaphragm calls.
I think they are Primos. They are the ones with the spacer for the roof of your mouth. They are the only ones to get, much more consistent sound.

Lightweight, can carry them in one shirt pocket, don' t cost a bunch, very versatile as to the sounds you can make.
I like to walk through the country banging around and blowing lots of cow and calf calls and small bugles trying to sound as much like a small herd with no herd bull as possible. Works great.

The type with the spacer for the roof of your mouth are really easy to master.
Mess around with them in your car on the way to work for a couple weeks and you will have it down.