Good rotating thread design, no jamming when you rotate it. The updated tile leveling system as the T-needles are changeable. And the T-needles are made of manganese steel, with a better hardness than 304 steel. The tile grout can be 2mm-6mm if you change tile spacer. 100pcs tile leveler, 500pcs tile spacer, 2 wrenches. We offer 360-Day Money-Back Service for any quality issues. Any dissatisfaction with the purchase within that period will be responded with a refund.