Covenant drop pod
From Halopedia, the Halo wiki
The Orbital Insertion Pod is a ubiquitous, one-man Covenant-manufactured high-altitude deployment vehicle. It is roughly cylindrical in shape, but with two tapered, slightly angular ends. It is made of burnished cyan-purple metal, but has an opulent, white interior with a contour that conforms to the physique of a Covenant Elite. Upon impact with the ground, the pod splits into two halves, revealing the interior and allowing the Elite inside to escape and move.
The Orbital Insertion Pod is a mode of transportation currently in use by the Covenant. When the Covenant decide to capture a planet rather than simply glassing it from orbit, they use orbital insertion pods to drop Elites to the planet’s surface as shock troops. Use of these pods is very hazardous and is reserved only for critical situations, or when a surprise attack is necessary. It is theorized that the pods are coated with an energy shield to disperse heat and are armored to withstand anti-air flak cannon fire. The vaguely coffin-shaped pods are small and cramped, with barely enough room for one Elite and his weapon, and there appear to be no restraints or other devices inside. Upon landing, the front of the pod blows off to allow exit, so the fronts are probably placed on the pod just before the drop.
These pods were evident around New Mombasa during The First Battle of Earth. They also appear in the level Uprising as several allies aid the Arbiter. They also appeared in the Halo 3 level Floodgate sent by Shadow of Intent to aid Spartan-117 and the Arbiter against the Flood infestation in Voi.
It is proposed that these pods are a Covenant spinoff of the Human Entry Vehicles (HEV)'s used by the ODST's, colloquially known as "Helljumpers".
An Interesting Side Note
It appears that the Orbital Insertion Pod was originally intended for orbitally inserting your penis into a vagina.
Dimensions
Height: 4.95 meters (16.2 feet)