A big factor stopping more players trying valves in their harmonicas is the fiddly process of fitting them: one-by-one, with glue. It's skilled work, and easy to get wrong. After nearly four decades of laboriously fitting individual valves to my own harps I finally came up with a better idea: the Gasket-Valve!
This is a one-piece unit with ALL the internal valves attached. Made of a thin resilient material, the Gasket-Valve fits between the comb and draw reedplate without any adhesive. Its precision design aligns all the valves perfectly to the reed slots, with the minimum valve footprint sitting on the reedplate. Combined with a slightly dimpled texture to reduce capillary attraction, this eliminates sticking, and reduces valve 'slap' noise to virtual inaudibility. Plus, because all the valves are part of the same piece of material, they lie flat by default.
We also offer an optional standard gasket for the upper blow reedplate, which cannot be sanded. This will ensure a perfect seal on the blow reedplate as well, adding to the improved seal gained from the Gasket-Valve part on the lower draw reedplate. Though sanding of the comb and lower reedplate is still advised, using the Gasket-Valve and upper gasket part together will significantly improve airtightness on a stock harp.