Rainbow Lifegard Automatic Chlorine/Bromine Feeders Years of customer use and satisfaction have proven the Rainbow feeders to be the performance leader in pool & spa chemical dispensers. Features: No special venting required, completely enclosed system, no escaping gases, all Lifegard feeders are NSF listed. Off-Line feeders: 300 Series. For existing pools or spas. Operates on pressure side of pump. Uses 1/4 In. feeder hoses, control valve and fittings.