Stop slipping resin vats and failed prints! This 4-pack of high-quality replacement knobs and bolts lock down resin vats securely on Elegoo 3D printers. Made of durable stainless steel with metric M4 x 40mm dimensions, hex head and precise threading to fit Elegoo vat knob holes perfectly. Far superior to flimsy plastic alternatives. Allows you to tighten vats into place with a wrench, preventing the shifting and leakage that ruins prints. Vats stay firmly where they should for print success. Ideal replacements for lost, worn or defective knobs that came with your Elegoo Saturn and Mars or other compatible models. Verify fit before ordering. Maintain the integrity of your printer's resin vat setup and avoid disrupted print jobs. These replacement bolts restore performance and confidence. Get a 4-pack so you have spares on-hand when knobs eventually wear out or go missing. Or secure multiple vat points for reinforced stability. Experience smooth, uninterrupted 3D printing without failed prints from loose vats. Precision metric stainless steel bolts offer a durable, reliable vat locking solution. Easy DIY upgrade takes minutes. Simply swap out old knobs for these sturdy replacements. An inexpensive way to protect your investment and printing results.