Check the listing for details. 4-Pack Replacement Knobs Screws Bolts for Elegoo Saturn Mars Resin Vat Tanks. Color: Black, Condition: New. Listed at 9.00 USD. 4-Pack Replacement Knobs Screws Bolts to Lock Down Resin Vat Tanks HEX Metal Metric Bolts M4 * 40 mm Length for Elegoo Saturn 1/2/3/S/8k Mars 4/3(PRO) 100% compatible with Elegoo ALL Saturn series of 1/2/3/S/8K models as well as Elegoo Mars 3 and Mars 4 Series Never stuck with half cured resin again - this knob has the LARGEST possible knob size without being in the way of the movement of the build plate Made of durable high quality steel with metric M4x 0.7mm threading with 40 mm length to precisely fit Elegoo printer vat tank holes Heavy Duty knobs to tightly fasten down the resin vat and prevent leaks. Stops vat wobbling or shifting during printing for smooth, even prints CAUTION: it's not compatible with Mars 4 Max.