Fur­niture is the largest of the spa­cing mater­ial.  Ori­gin­ally wood, it is sup­plied in ems rather than points.  Find­ing wood to suf­fer from warp­ing and eas­ily dam­aged, print­ers began to use metal fur­niture (from the same mater­ial as spaces), and then alu­minium girder pat­tern fur­niture which was lighter.  One devel­op­ment was the use of a Formica-derived mater­ial called Resal­ite.  Steph­en­son, Blake claimed this was bet­ter than metal fur­niture because dam­age on one dimen­sion would not cause prob­lems with accuracy.