The John Guest MI4512F4SLF Brass Connector is a high-performance, lead-free fitting designed to bridge 3/8" OD plastic tubing and standard 1/4" MFL (Male Flare) ports. Commonly found on CO2 regulators, gas manifolds, and keg couplers, this connector allows for a rapid, tool-free connection while maintaining the robust integrity of a brass flare seat. The lead-free brass construction ensures compliance with safe drinking water standards, making it ideal for both brewing and soda applications.

Featuring John Guest’s world-renowned push-fit technology, this fitting provides a permanent, leak-proof seal that can be disconnected and reused without damaging the tubing. The internal stainless steel collet teeth provide a secure grip, while the high-quality EPDM O-ring ensures an airtight seal. This specific fitting is essential for technicians and homebrewers who want to upgrade their gas or liquid lines to a modular, easily maintainable system.