Aha, a Highline Kites / Berkeley Kite Festival special... Fabric is from Ken Conrad, I believe.
Not a common skin, specially made for Highline - you're not likely to run into another one on the field, except on a very blue moon.
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All 1.5 frames (SLE, B-Series, EXP) are interchangeable, same length spars all around.
Difference between SLE and B for you at this point, is negligible - IF you have the 1/4" spars, not the thicker SLEs.
I'd say a properly tuned SLE with 3 wrap leading edge is 85%-90% of a B's overall performance with the same frame.
That being said, the B-PRO is perfectly sewn by a master kitemaker, comes in totally custom colors, and uses PC-31 Icarex instead of the regular stuff... It's a bit more, sure, but really worth it if you're likely to keep at it for a while.
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2 wraps are spongier, if you're not crashing at terminal velocity, go right for the black race rods, for sure - we don't use 2 wraps any longer.
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A better kite is worth more than better handles, far and away.
However, the "snagless" PRO handles from Rev are pretty sweet and look super cool.