Good source for spindle extenders?

Based on recent fit changes. I need to get 30 mm pedal spindle extenders. Anybody have a good suggestion other than through Amazon.( personal boycott for all time.) Can pedals be removed if one switches type?( i.e. Look to Shimano)
Thanks

Steve Hogg sells some. https://www.stevehoggbikefitting.com/store/bike-fitting-products/pedal-extenders/

though i recognize you’re not an amazon fan, maybe you’re OK with aliexpress? our friends in china will mail you a set for 5 bucks . . .

i actually use them semi-often for bike hardware and have mostly been happy; there’s always a risk factor and after a few failed experiments i won’t buy MTB seatposts from them, for instance, but for little fiddly bits like this i often find they’re great.