We are all using 20mm aluminium from the local hardware store, About 1.2mm wall thickness, It does break if you do bend it put it on your knee and straighten it up. i have done the upgrade of adding some black sail number insignia cloth on the aluminium, to give it a bling look, And the best part is they cost about $10.00. And if they do break ( this is my 4 season with the original) it not too much to replace
Just my 2 cents worth
Richard