You can’t go wrong with SAEC SS-300 mat. It fits SP-10MKII platter, SP-20, SL1210mkII platter, i mostly using my SS-300
on Luxman PD-444.
Saec SS-300 alloy mat (870g) eliminates the distortion-producing resonance in the 200-400Hz range, which is common to most all conventional rubber mats. This results in a 10~20dB net reduction in overall resonance, to further reduce distortion at its source. Some cartridges are sensivite to the rotor under the platter, felt mats can’t solve the problem.
Honestly, I don’t know any better matt for the price under $400