PE-Xa Rings for cold expansion fittings are designed with a stop edge, they are used in conjunction with a PEX expansion tool (expander) when installing PE-Xa type pipes with expansion style brass or poly PEX fittings. The characteristic of our PE-Xa rings are high cross-linking degree up to 85%, compatible with our PE-Xa pipes very well. Made to ISO15875.3 /ASTM F1960 standard.