B-Series fits all B series engines (B16 B18 B20 All variations)
H-Series fits all H series engines from preludes of all years.  Will work with H series swaps in Civic/Integra as well.

Some general info you need to know.
1)  Will not work with Power Steering - You don't want it anyway
2)  Will work with the stock timing belt cover, however you will need to do some trimming
3)  Works Kevlar belt or OEM belt

Why a secondary timing belt tensioner?
1) Have you ever seen a car on the dyno with the timing belt exposed?  The long side of the belt at the front (between the Exhaust cam and Crank Pulley) has a travel distance of aprox 12" with no tensioner.  The belt flaps over 1" while under load at high RPM.  Why is this a problem?  Your cam timing is very important at high RPM and this flapping creates a variation between the crank and cams.  However small you may think it is, remember how fast the motor spins and how many revolutions per minute were talking about.   The difference will throw your cam timing and spark out enough to cause a timing difference.   The pulley keeps the long side of the belt tight which keeps your timing in check.  Many pro racers have been building and using these for years on their own cars with self machined parts and OEM pulleys.  Finally a commercially available product for your street/strip car is available.  

2)As you run a really high lift cam you run heavy valve springs to eliminate valve float.  Much heavier valve springs puts a lot more tension on your timing belt.  The tensioner then places much needed additional pressure on the exhaust side of the timing belt to help stop the belt from flapping knocking out cam/crank timing.  The higher you rev your motor the more pronounced these problems become.

3)On the Vibrant Performance / ETDRacing all motor drag car we run high lift cams (.590 lift, read huge) and heavy valve springs.  All the tension on the cam gear from those huge cams lift caused the gear to slip back a tooth on our Kevlar belt when the motor was being turned off.  As the motor slowed down to a stop the cam was left on a heavy spring and it rolled back and skipped a tooth because of the slack in the belt.   After we developed the tensioner we eliminated this problem and have not skipped a tooth on our cam gears since.   The product came as a solution to a problem for our very own race car.   We were lucky and noticed it moved with marks we placed on the belt and cam gear, one of our fellow racers was not so lucky and bent a few valves.

Product Details
CNC machined from Billet 6061 Aircraft Grade aluminum. 
Clear Anodized coating on machined bracket
Pulley is coated with special Black coating used by OEM manufacturers designed not to wear out the timing belt.
Bearing designed for 30,000 rpm of continues use will last a life time.
Allows for total adjustability both vertical and horizontal