The "Fender Classic Celluloid Pick Shell M" is a traditional tortoise shell style plectrum.
After trying many plectrums I finally settled on these, they are not modern high tech, "go faster", shredding picks, no grooves, dimples or gimmicks here, they are just a good quality, plain, traditional styled plectrum.
I used to play with Dunlop picks but found them quite slippy, no such problems with these despite them being a plain / smooth pick.
They seem to be a bit harder than other tortoise shell style picks such as the Thomann own brand tortoise shell picks, harder in a good way as far as I'm concerned, I find them a joy to play with, accurate picking is easy and bright but don't forget to try a reverse grip which gives a fuller and more ragged sound, well worth trying !!!
These are very durable, they don't wear out easily, they don't break or chip.
I use (M) Medium for electric guitars but I tend to use the (T) Thin version for electric 12 string and all my acoustics.
These are available in white celluloid as well, they are the same pick just a different colour, I use Medium in tortoise shell and Thin in white so it's quick and easy to tell them apart.
