Rock take the lead to adopt the US Thermtool high frequency welding technology , now we have about 25 advanced spacer production lines, more lines will be introduced in future, Rock serves a high-end Aluminum spacer for the insulating glass.Rock now make it headquarter in Beijing. our products are very popular with worldwide market.About aluminum spacer bar. Size from 4mm to 40mm.-5.5 7 7.5 and 8.5mm side welding line spacer bar have been put on the market 100% guarantee bendable.-Our spacer bar surface very shine, and welding line smooth.About sealant;Our silicone will not become crisp and crack subzero 30 degree, and will not become soft, degradation at 90 degree.AboutButylWater vapor and gas permeability lower to 0.2g/(㎡.d). Quality is similar as Germany Kommerling, pass SGS certificate