3/8in. OD tube compression fitting. Blue-White P/N 71010-323. The A1-2T, A1-1T and A1-3T are made of Tygothane, the most abrasion-resistant plastic tubing for chemicals such as chlorine. Excellent stability even when exposed to grease, oil, or fuels.
The A-100N has been upgraded with an all new pump head and tube assemblies. To allow new style tube assembly to old head see the Retrofit Kit.