I use Opposite Wall frames. I chose their frames since they are designed in Montreal! They are lightweight and sustainably sourced. In addition, the works are protected by crystal clear plexiglass and it is unbreakable!
 Metal frame width: 0.4 inch. Frame depth: 0.8 inch.
 Oak frame width: 0.6 inch. Frame depth: 0.8 inch.
 *** Square frame 12',x12'' or 16''x16'' : Allow 2 weeks for delivery ***