Photogels Strobist Premiere Color Correction Gels and Special Effect Gels Kit, 18 Lighting Gels Precut to 2x5-Inch with Velcro for All Speedlight Flashes The best selection of 18 gels for Color Correction and Special Effects Color Correction Gels: CTO, CTB, Plusgreen gels in Full, 1/2 and 1/4 strengths Special Effect Gels: 1/2 Stop ND, 1 Stop ND, 2 Stop ND, Red, Green, Yellow, Magenta, Light Blue, Dark Blue