Each low speed needle is composed of two main parts: head and needle. Thru the years the Linkert & Langsenkamp factory produced different types of heads on the same needles. Type 1 features a Ø 11/16” top knurl and a Ø 1/2” lower knurl, while Type 2 features two equal Ø 1/2” knurls. Type 1 was used by the factory thru 1947, Type 2 from 1948-1965, often with the same part number.