Box One Mini Seat or Pro Echelon Large
The Box One Mini Seat is a Carbon Seat and Post Combo that is 22.2mm x 135mm long. Its also made in 27.2mm seatpost diameter. This seat fits 22.2mm seat tubes which are common on Micro Mini, Mini and Junior BMX frames and bikes. This one weights 5.4oz which is super light for a seat and seatpost combination. The Post is 135mm long. The seat is hard plastic.
Box BMX Parts are among the very best of quality brands. Check out the Box Website.
The 22.2 has cutouts in the seat. The 27.2 does not.