Euroboor Twist drill bit with 3/4" Weldon shank that allows you to connect directly to any mag drill with this standard size arbor. Size of bit is 5/16" x 2". Eliminates the need to connect a chuck. HSS high quality twist drill bit for durability. Twist drill 3/4" Weldon, 3/8" Diameter x 2" Length SPI.3/8