Brass body compasses are a 100 year old tradition with hunters. Time proven design, used by Admiral Byrd, Admiral Perry, Charles Lindbergh and Teddy Roosevelt and in WWII, Korea and Vietnam. CNC precision-machined from solid hi-grade brass bar stock. Each fits together with no defects that could cause inaccurate readings. Strong malleable brass casing won't rust. Movement rotates on ultra smooth agate jewel bearing. Virtually shatterproof crystal. POCKET: Handy swivel ring allows user to attach to lanyard for easy carrying. PIN ON: Uses large brass safety pin to fasten securely to jacket or shirt.