At Alpha Metals, L0 means no halide in the formula; this is true for liquid fluxes and solder pastes. UP78 is REL1, and it passes AgCrO4 paper. We consider it a Bellcore compliant paste, but it's still REL1. It is REL1 because it's formula contains halide. Take a look at our technical bulletin. UP78-OSP is REL0, it has no halide in it's formula. We don't add any halide to it. Any trace halide in UP78-OSP is from trace halide contaminants in the raw materials, very, very tiny. ################################################################ TechNet E-Mail Forum provided as a free service by IPC using LISTSERV 1.8c ################################################################ To subscribe/unsubscribe, send a message to [log in to unmask] with following text in the body: To subscribe: SUBSCRIBE TechNet <your full name> To unsubscribe: SIGNOFF TechNet ################################################################ Please visit IPC's web site (http://www.ipc.org) "On-Line Services" section for additional information. For technical support contact Hugo Scaramuzza at [log in to unmask] or 847-509-9700 ext.312 ################################################################