Here's what TAMA say about the HT830B Round Rider XL Throne:
The Round Rider features a traditional and gently rounded cushion shape that is very popular due to its versatility. This new extra large Round Rider XL seat provides the same classic shape with a wider surface area and a thicker seat.
Details: Height adjustable range: 515mm-670mm (20 1/4" - 26 3/8")
Round Rider XL Seat
In order to support diverse playing styles and provide the maximum in playing comfort, Tama developed the extra large and super-padded Round Rider seat top.
Glide-Tite Grip Joint
This Glide-Tite Grip Joint allows for a more secure attachment by using a metal-to-metal contact point. It is an extremely solid base attachment, even for the heaviest hitters.
This is a great design that utilizes two-piece locking hinge collar system for superior throne base to seat connection and oversized wing nut for easy and secure tightening. TAMA removed the "wobble" which can typically affect the seat to throne base connection.
Super Stabilizer Design
By lowering the distance of the center throne pipe to the floor, a lower center of gravity was achieved. Additional stability improved by lengthening the tripod leg stabilizer bar and designing double-braced tripod legs that do not taper at the point they insert into the rubber feet.
1st Chair Height Adjustment
1st Chair's height adjustment system which blend threaded rod throne with the T-bolt system offers easy and fast height adjustment.
Oversized Rubber Feet
The extra-large rubber feet are 1.5 times larger than previous TAMA rubber feet to optimize stability.
TAMA's "Rocklok" features a specially designed Nylon Bushing at the bottom of the throne's threaded rod that prevents side-to-side motion within the base.
This special feature provides exceptional durability and stability.
It's tough to imagine just how much weight and stress is on the rubber feet of your stand-until you see how often you have to keep replacing them. Not so with Foot Life. An innovative plastic leg attachment, Foot Life eliminates the wear and tear of metal to metal contact for longer foot life.