The contrabassoon, also contrafagotto or double bassoon, is a larger version of the bassoon sounding an octave lower. Its technique is similar to its smaller cousin, with a few notable differences.

The reed is considerably larger, at 65-72 mm in total length as compared to 53-58 mm for most bassoon reeds.
(wow O.O how to put inside my mouth?)

Fingering is slightly different, particularly at the register change and in the extreme high range. The instrument is twice as long, curves around on itself several times, and, due to its weight and shape, is supported by an endpin rather than a seat strap. Additional support is sometimes given by a strap around the player's neck. A wider hand position is also required, as the primary finger keys are widely spaced.

The contrabassoon has a water key to expel condensation, and a tuning slide for gross pitch adjustments.

(lols. interesting.. still got tuning slide, water key somemore.)

The instrument comes in a few pieces (plus bocal); and can not be disassembled without a screwdriver.
(disassemble also must use SCREWDRIVER? crazy.)

Sometimes, however, the bell can be detached and in the case of instruments with a low A extension the instrument often comes in two parts (plus bell and bocal).

http://en.wikipedia.org/wiki/contrabassoon

Contrabassoon is soo interesting ^^ I shall try on it if i ever have that chance. =.= So i'm lazy to copy & paste the rest =p Oops... my stomach is scolding me. Bye, off to lunch.