USB drive enclosures with spin down

Hi.

Does anybody know of a USB hard drive enclosure that supports drive spin
down (either manual or automatic) under Linux? I've bought a cheap
enclosure but it doesn't allow me to spin down the drive (and after more
than 24 hours of inactivity it hasn't spun down automatically).

Thanks.

-- 
Bruce Guenter <bruce_at_untroubled.org>                http://untroubled.org/