As previously mentioned these are probably MS01-CA for DECstation 3100 or DECstation 5000/1xx or Personal DECstation 5000/xx. Note that MS01-AA (a pair of 2Mb SIMMs) and MS01-CA (a pair of 8Mb SIMMs) cannot be mixed - well they can but then the 8Mb SIMMs pretend to be 2Mb SIMMs, i.e. 2Mb+2Mb + 8Mb+8Mb => 8Mb. Doug. PS - Anybody got any to sell - I'm looking for 3 MS01-CA, i.e. 6 x 8Mb SIMMs for a total of 48Mb.