Product Name: Drill CollarsPlace of Origin: ChinaFeatures: 1) Manufactured from AISI 4145H or 36CrNiMo4 modified steel, with rolled-like surface finish, alternative surface finishes can be provided 2) Made in accordance with API SPEC 5D standard and can be divided into two groups: a) Group 1: grade E drill pipe b) Group 3: all high strength grades drill pipes (grades X-95, G-105, S-135)