The gen 2 Whizzer speedos show up on ebay from time to time generally sell in the $40-50 range.. The yellow face originals will fetch nearly $400 if complete/perfect. The cheapy analogs in my experience are way inaccurate, generally on the fast side. I have 4 of em and checked em with GPS, some were neary 8mph optimistic But its the only thing to use on a vintage bike build. Im not sure the sellers know sometimes exactly what size wheel they really fit. I just ordered and should have today a tire drive cheapy($11). Curious to see how it works.