For Prime members only, Amazon offers the Kohler Touchless Toilet Flush Kit, model no. K-1954-0, for $33.33 with free shipping. That's $17 under our mention from two weeks ago and the lowest total price we've seen. (It's also the best deal now by $22.) It's compatible with most canister and flapper toilets, but not with dual-flush, top-mount flush, pressure-assist, or ballcock valve toilets.