Description for H sections: 1st internal Depth 'Board Size' - 2nd external widths - 3rd thickness | M = metres, mm = millimetres
3mm plastic H section is designed to 3mm fit boards. Both the external widths of this product are the same measurement. If you require unequal legs then see our H joining sections (Unequal) range. H section joining strips 3mm are often used for joining boards and panels. 3mm plastic H section is available in white and black.