Photogels Strobist Ultimate Color Correction Gels and Special Effect Gels Kit, 25 Gels Precut to 2x5" with Velcro for All Speedlight Flashes The best selection of 25 gels for Color Correction and Special Effects Color Correction Gels: CTO, CTS, CTB, Plusgreen gels in Full, 1/2, 1/4 and 1/8 strengths Special Effect Gels: 1/2 Stop ND, 1 Stop ND, 2 Stop ND, Red, Green, Yellow, Magenta, Light Blue, Dark Blue