Professional Compatibility: Designed for X3 waterproof case, easy to install, just one buckle. Red Filter: Suitable for 5-25 meters diving shell depth, suitable for sea water, correcting the greenish color. The water red light above five meters is sufficient, and generally there is no need to use a red filter. Purple Filter: Suitable for diving shell depth of 5-25 meters, suitable for fresh water, correcting greenish color. perfect for in freshwater lakes or lake environments where the water is green due to algae. Pink Filter: suitable for depths of 1-5 meters diving shell, commonly used in snorkeling freshwater waters or seawater waters, to correct bluish color. : This filter uses optical coating to effectively get clearer pictures during . Colour:Red & Pink & Purple Material:Acrylic Package Contents: 3 x Dive Filter 3 x Tool Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.