The Fowler 52-104-000-0 Screw Jack set features a capacity of 1000 lbs. and a range of 2.25"-3.375" before extension use. The Jack base diameter is 1.25" with extension bases 1" and 2", which can be stacked and combined for cylindrical applications or narrow edges and slots. This jack set includes Screw Jack, two optional bases, 1 " and 2" extension, locking bar, and optional support. Adjustable with a pivotal top or a single contact point extension. All in a shop hardened case with a full 1-year warranty offered by Fowler. Fowler, an American company, manufactures premium inspection and measuring instruments like electronic indicators, calipers, bore gages, and micrometers. The company, founded in 1946, is headquartered in Canton, MA.