Due to the supply shortage of ERL-4206, ERL-4221 has now been specially formulated to replace it. ERL 4206 is one of the main components of the low viscosity (Dr. Spur) embedding resin kit. ERL-4221 is a Cycloaliphatic Epoxide Resin.

A light colored, flexible epoxy. CAS #: 041638-13-5 Specific Gravity: 1.14 Epoxide equivalent weight: 175-205. Used to simplify infiltration in combination with Epon 812 (Embed 812). Kushida, J. Electron Micro., 16,278 (1964)