T88-GDK(B2), Sliding 2.5 Track Fixed Frame. Is used for a sliding window/door frame system.

Track Fixed Frame
• Refers to 88 mm series profile
• Used for Large windows / balcony doors
• Better strength & durability
• (B2) Refers to Frame Type / Variant
• 2.5 track frame configuration
• Fully fixed to wall, Strong, non-movable structure