Inside diameter is 5/8".
A.M. Leonard, Inc. warrants its tools identified as "Leonard Premium tools" to be free from material or workmanship defects for the life of the tool. A.M. Leonard, Inc. will replace or repair faulty tools at its sole discretion. Tools need to be sent postage prepaid to A.M. Leonard, Inc. 241 Fox Drive, Piqua, Ohio 45356. This warranty does not cover damage due to abuse, rust, mishandling or unauthorized repair. Changes in design, finish, material specifications, etc. may be made without notice and without implying any obligation or recourse upon A.M. Leonard, Inc.