Website design & usability -- can you help shorten a couple of words?

On MikaMaya Art, I need to gain just a little space in the first column of a table of painting sizes. The link above goes right to a page with such a table. Right now, the first column says Size, and that’s crystal clear. But I need to add the ability to toggle the display there between Inch and CM display. So I need it to say something like
Size in cm

Viewers who prefer Metric measurements will be able to click on the cm link to see it in metric measure. Clicking in would toggle them back to the inch display, which will come up as the default.

To gain space for that, I could shorten the column headings Depth and/or Select. But what shorter piece of text would adequately define what those columns contain? Fluther wordsmiths and website usability critics. Help!