Collet ER, according to standard DIN 6499, form B, type class 2, size ER 20. Brand Gurfer with reference ER20-2.
Also available: set of ER collets, DIN 6499 B CL2, size ER 20, Ø 2,0 - 13,0 mm per 1 mm, 12-piece, in plastic storage case (ref. ER20SET2).
For mounting tools with straight shank.