SPI Supplies Brand Catalase Suspension, 500 mg
Prepare your own catalase calibration specimens. While we don't recommend this for everyone, since there is some amount of "art" required to make good specimens, in some microscopes and under some conditions, the beam characteristics are such that the typical specimen does not last very long, therefore the reason why one might want to make their specimens.
The real advantage of the SPI Catalase Crystal Suspension, is that one is freed from the burden of having to go through the tedious recrystallization process described by J. Wrigley in J. Ultrastructure Res. 24, 454-464 (1968).
If this all sounds a bit tedious, then consider purchasing instead, a catalase grid already prepared by the experts at SPI Supplies.