ASPR (Aspr) SL Series This is a top and bottom set for the TE-01C13 and TE-01S13. Aspr is a Japanese high-quality drumhead specialty brand developed by Aspr Co., Ltd. In particular, for snare drums, the SL series, which uses the unique aramid fiber "Technora" for high durability and sound quality, and film heads with annealing processing are highly regarded, and they support a wide range of pitches from low to high.