Silicone R5 O-ring A silicone O-ring, functionally equivalent to the EPDM F_331 and matching Nuova Simonelli part #02290016, silicone offers better heat resistance for hot-water and steam-adjacent applications compared to standard EPDM. SPECIFICATIONS Silicone construction COMPATIBILITY Fits: applications specifying the R5 O-ring size Replaces: Nuova Simonelli part #02290016; functionally equivalent to EPDM F_331 INSTALLATION An easy DIY swap, lightly lubricate with food-safe silicone grease before seating to avoid pinching during assembly. PRO TIPS Silicone and EPDM O-rings of the same size aren't always drop-in interchangeable for every use despite being "equivalent", silicone handles heat well but has lower abrasion and compression-set resistance than EPDM in high-cycle fittings, so stick with whichever material your specific application originally used if you have a choice.