Perfect Match: This RV toilet seal kit is precisely engineered for Dometic 300, 310, and 320 series toilets, directly replacing parts 385311652 and 385311658 for a factory-fit solution. Not compatible with 210, 510, or other unlisted models, so please verify your toilet model number carefully before purchasing to ensure proper fit and function. Precise Product Dimensions: The 385311658 RV toilet flush ball seal measures 3.9 inches outer diameter, 2.75 inches inner diameter, and 0.27 inches thickness to match the original part. Solves RV Toilet Leakage & Odors: When the original seal cracks, warps, or wears out, it can cause persistent water drips and unpleasant odors in the bathroom area. This RV toilet seal kit restores the sealing performance of your Dometic toilet, helping to eliminate foul smells, reduce moisture buildup. Easy DIY Installation: Installation can typically be completed in just a few minutes with basic tools. Turn off the water supply, remove the old flush ball seal by popping it out without fully disassembling the toilet, and press the seal into place with the "THIS SIDE UP" marking facing up. A Happier, Cleaner Journey: This 2-in-1 combo kit includes both the upper flush ball seal and the lower base seal plus mounting hardware, offering a complete maintenance solution in one purchase. Color: Black Material: Metal+Plastic Package Contents: 1*Toilet Sealing Kit Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.