Material: cellulose acetate
Manufacturer: Boye, USA
US Patent: 1935 US 2024794
Length: 5 1/2 ”
Sizes: E, G, H, J (probably the whole range from D or E through K)
The Boye cellulose acetate hook introduced in 1935 had the above labels. The non-inflammable was intended to differentiate this cellulose acetate hook from earlier celluloid hooks made by other manufacturers that could burst into flames if placed too near a heat source. The patent number refers to the patent for the hook shape which was also introduced in 1935.
The label on cellulose acetate hooks was later simplified to the size line with a price. This probably happened about 1945. War production would had severely reduced crochet hook production, the hook shape patent expired, and celluloid crochet hooks were no longer produced.