I borrowed my sister's Hoover carpet shampooer and noticed she had lost one of the caps to the water tank. I found a similar replacement cap at www.thingiverse.com/thing:4546785 but it was for cap with only 3 prongs to secure it to the tank and I needed 4. I removed all the prongs and then added 4. I printed the gasket (no modifications needed) in TPU and the cap in PLA. Fits better than the original :-)