Essentially, armor for the Swiftstrike Buckler, except instead of increasing ASI, it increases MSI by high, and when stacked, results in maximum MSI.
This outfit isnt necessarily good, as it remains 3*, and has incredibly low defence. It's mostly just a mess-around item, that people use for fun, like the cutter line.
Which brings me to the next one, another cutter line, called the Swiftstrike Saber, which looks like a yellow Red Saber, with additional effects (similar to the aura around the Swiftstrike,) whenever you swing.
It is similar to the striker, but less attack, and somehow faster, (even though striker is next to max speed.)
And then, the Swiftstrike Aura, which is essentially that little aura thing that comes from the Swiftstrike Buckler, except you can attach it to things.

Swiftstrike Saber (3* only.)

Swiftstrike Suit (Yellow Spiral Flak Jacket with additional Swiftstrike Aura, 3* only.) --- everything but Aura Slot.

Swiftstrike Sallet (Yellow Spiral Sallet, with the top color expelling Swiftstrike Aura, similar to the Surgebreaker Helm, 3* only.) --- Everything but Top Slot.