I think it’s pot luck if your pedals are compatible. Still haven’t finished putting them onto the shoes, mostly cos the spare-spare pedals need the big allen key on the cranks.
Last time I had a pair out of China they wore down quick on the contact points to the ground, but for pennies who cares?
I picked up a set of these today. Seem to work with the Shimano PD-R540 well. They come with bolts and a 4mm allen key. Not bad for £3!