When you need to custom cut several sizes of spiral boning for theater or opera costumes, this coil of spiral steel boning for corsets is the wholesale way to go. Flexible front to back and side to side. 

Using a heavy duty wire cutter, clip the wire on the outermost left and right side of at the length you desire and the center coils will pull away without springing. Don't forget to pick up some bone tips to cap off the loose ends.