Ferrite Toroid Core 77-1
If you are building a low to medium powered DRSSTC Tesla Coil, SSTC, or other type of power bridge, then these are perfect for both the gate transformers and current transformers. Use two of them with 32 turns per core, cascaded for a 1000:1 current transformer.
Dimensions: 1.00" x 0.061" x 0.50"
Click here for the datasheet (PDF)