These IIAR-compliant pipe markers come with the traditional yellow background and are recommended for use in labeling ammonia piping and its contents. IIAR pipe markers should include: the marker body (AMMONIA), physical state, pressure level, directional arrows, and an ammonia piping abbreviation Style 4 pipe markers measure 1-1/8 in. x 7 in., comes with four markers per card and fit pipe diameter 3/4 in. to 2-3/8 in. B-946 Pressure Sensitive Vinyl is printed with weather-resistant inks and is suitable for indoor and outdoor applications Use with directional arrow pipe markers or banding tape