This trap is a # 44 Blake Lamb Co double under spring trap with Morse Oberto's #400 dogless pan conversion. This is the largest size of the Morse Oberto dogless assembly and resulted in one of Oberto's favorite beaver traps. The Oberto dogless assemblies were patented and produced mainly in the 1950s and were made as improved replacement dogless triggers to be user installed on traps of various sizes. This trap and trigger are complete with strong springs, complete chain and ring and a #400 size dogless assembly that is clearly marked with size number and the Iron Belt Wis address where it was manufactured. The trap has a jaw spread less than 5 1/2 inches as required by eBay protocol.