P2 – A laminated inner pane double glazing unit with the anti-burglary topSafe system. Glass construction from outside to inside is 4H-Yg15Ar-33.T. The outer pane is made with 4mm toughened glass and 15mm warm TGI spacer filled with inert argon gas. This glazing type produces a U-Value of 1.3W/m²K and has an acoustic rating of 35dB. Available in standard roof windows and the D_G flat roof window range.