Here is a front and rear Onza H.O. (high output) vintage cantilever brake set.  These came of my bike some time ago and been sitting around my spare parts pile for way to long.  As you can see in the pictures, the part the brake pad clamps on to are cracked.  Only one complete non-cracked brake the rest (3) are cracked. However, I did still ride with these even when they were cracked and seem to hold up fine.  With that said, all the parts should be there to mount them on a bike but maybe best used as spare parts. No pads included.