I collect all the Silca pumps I can find! The square tops are older than the fitted and hard to find these days. They require the umbrella hood to mount and length is more forgiving because of it. The fitted ones need to be sized to fit a frame tube. There were at least 3 heads available: the Silca plastic, the Campagnolo plastic and the Campagnolo steel. The Campagnolo steel is the only one worth messing with.

They work surprisingly well. If you pump as hard as you can you can get 90-100 pounds. There's a knack to putting them on the presta valve as its easy to blow the handle out of the pump. Press the valve first to make sure its working. Likewise, grip the head with your hand around the tire to keep from breaking the valve as you pump.

Inside there's a leather cupped washer. You can pull the handle, flare the leather and coat with white grease to form a better air seal in the tube.

I think there the best pumps ever made. For years in college, its all we had.

As far as I know there were only the 2 types... both plastic.

Lots of colors back in the day, they're obsolete today, though NOS seem to be on ebay all the time for outrageous prices. Sometimes you can find a deal.