Each model of GT-ISL has a very low table for the original flat table, which has three T-Slots. Original table heights of the machines are as follows. GT-5 is at 45 mm or 1.77, GT-7 begins at 55 mm, or 2.1, the GT-10 starts at 70 mm or 2.7 center height, and the GT-15, which starts at 96 mm, or 3.77 center height. The riser plates are offered in 12" or 17" to cover the entire table for the GT-ISL25 and GT-ISL-35 which the 17 riser cover the entire t-slot or the original table. We offer 12" riser plates for the GT-10 and GT-15 models. The machines original table is 24" so if you want to use tool holders on the entire travel of the models you would purchase two 12" riser that would cover the original t-slot of the machine. This flexibility allows us to install much larger live tool spindles and grinders on the machines and allows us to offer much stronger tool holders and tooling to compliment the larger motors and ball screws of the machines. Optional center height riser tool plate tables available on request.