1018 Steel T-Slot Nut, Black Oxide Finish, Grade 5, Tapped Through, 3/8"-16 Threads, 5/8" Height, 9/16" Slot Depth, Made in US (Pack of 5) Material is case hardened 1018 steel with black oxide finish 3/8"-16 Thread 9/16" Table slot 1-1/8" Base size Measures 5/8" width by 7/8" height