HP-41 - Memory modules

[albertofenini]

Hi everyone,
it may be a stupid question, or may be I'm just too lazy to look into the documentation.
We are starting to clean and restore our Coconut units,
so far we have brought back to life two card readers and we will work on the units soon,
will also post pictures if of interest.
However, between the pieces we have some extended memory modules.
How can we check if they are working ?
Question is, what's the command we can type to check the basic capacity of let's say an HP41C
and then once added the module retype the same command to check if size has increased ?
Thanks everyone and apologies if it is a easy one ...