Schick

Peter Schick was a textile manufacturer from Frankfurt. The company Schick has constructed double hose regulators using its own name.
Unfortunately, there isn't much information left today about these regulators, but can be assumed that they were constructed using some parts (membrane, hoses and mouthpiece) of the double hose Air Master from Swiss Company Apag.

The German company Schick seems to have been in the 60s only a few years with regulators on the market.

One of the regulators produced was the "Safety Scuba". It was as a single-stage regulator. It was made with a hole in the middle of the upper lid. A comparable construction appears on regulators - Sea Horse MKI and MKII - from British manufacturer Submarine Products.

Probably, this hole (diameter of about 3 cm) allowed the diver to access the existing by-pass device under the diaphragm. When the diver needed extra air supply (in any emergency or to assist the removal water of the hoses), he pushes this device with his hands through the existing hole.

The other double hose regulator manufactered by Schick was the S.C.U.B.A.. Basically, this regulator is the same regulator "Safety Scuba" with a new case, but inside it has the same mechanics.

Both regulators are very rare today and Schick likely has constructed a small quantities of them.

Reference:

1. Deutsche Hersteller, Tauchgeräte und Faltenschlauchregler - by Frank Werthwein - Tauchgeschichte Spezial 5/2015, Kapitel 11