RedPhos Membrane Phosphatase Substrate is a colorimetric phosphatase substrate useful in immunoblotting and dot blot procedures. It produces a strong red reaction product with sensitivity in the low nanogram range, sharp band resolution and a clear image. The color produced is linear over a wide dynamic range and resists fading when exposed to light. A second product, BCIP/NBT Phosphatase Substrate, produces a deep purple precipitate at the reaction site and demonstrates similar performance characteristics to RedPhos. Both products are supplied as convenient one-component solutions.