3 Pcs 5/8'' -11 Thread Angle Grinder Shaft Extension Connecting Rods 5/8'' shaft extension are made of aluminum alloy. 5/8'' shaft extension are made of aluminum alloy Suitatble for all 5/8"-11 thread Polisher and Angle Grinder 3 Size Optional, 2.9 inch, 3.9 inch, 5.5 inch. Note: you can connect them to a longer length as request Stable installation with Precise thread,make sure the polisher or grinder working smooth without loosening The angle grinder shaft extension can help you reach the narrow, tight or awkward place which normal grinder or polisher can not touch, It needs to be matched with various grinding heads, grinding wheels, grinding discs and so on