Evans TT13G1 13-Inch Vellum

With a single ply of 10mil film that blends bright tone with greater sustain and sensitivity, the Evans G1 sets the standard for an open, expressive sound. Tune it low to get a cavernous rumble that emphasizes the natural sound of the shell. This drumhead incorporates Evans Level 360 Technology for ease of tuning, extended pitch range, and optimum quality of sound.

https://www.oosthavens.co.za/product-category/drums-percussion/vellums/