Milward Netting Fork - Hairpin Lace Tool No.4/0
Milward Netting Fork - 251 4201
This is a Hairpin Lace Tool or Hairpin Crochet Fork and I have heard it called a Crochet Loom.
This is a fork style 60mm width and 180mm length.
I have a great book from Annies Attic - Learn to do Hairpin Lace.