use to file the fret ends, 

nice quality products,

Two options

Beech hardwood block with file set at 45 degrees 

Flat underside

120mm by 50mm by 24mm

Maple hardwood block with file set at 35 degrees

radiused underside with 405mm radius ( R16 )

176mm by 60mm by 27mm

Muspor beech double sided block

has a 90 degree file and a 35 degree file, it is 145mm long.