The Cleansweep Eleven was released in 1995 [Y15], making it the latest broomstick in the series. Ron Weasley received one as a reward upon being made a prefect (OP9). He was very happy about it, so we know a fair bit about its specifications from him:
It can go from nought to seventy in ten seconds (OP9). This is presumably in miles per hour, as broomstick speeds are typically expressed that way (QA9).
The handle is made of Spanish oak (OP9). Note that oak is a wand wood (PS5).