White Royal Mail PIP Large Letter Postal Boxes C4 C5 C6 FROM UK MANUFACTURER
This equates to a maximum sizing of 350 x 250 x 25mm and a maximum weight limit of 750g and will fit through a standard UK letterbox (EXCEPT C4 Deep). C4 Die-cut 322 x 229 x 20mm Large Letter. C5 Die-cut 220 x 160 x 20mm Large Letter.