i am 90% certain Silca did make a locking type head for their pumps at one time.. i saw at least two for sale at t-town a couple years ago and sort of regret not buying one.. they were rather narrow, presta only, and had a wire bale about spoke diameter that performed the locking operation..
or maybe both these owners decided to upgrade their silcas with the same aftermarket pump head ??
andrei padlowski
ny, ny