These are a set of JE 1.8t 20v pistons, for all 1.8t 20v. This particular set builds a 2067cc 2L stroker engine, when used with a MK4 TDi Crankshaft (06a late 1.8t block). This increased displacement yields more power on the same boost, less chance of detonation at a given power level (Lower peak cylinder pressures) and faster spoolup. One of the biggest differences people tend to notice is the extra "grunt" around town, it really does make a difference to driveability! This is pretty much the most displacement you can possibly get out of a standard 1.8t block. Not recommended for early 1.8t blocks.
JE are a great upgrade for someone looking to build a stout, reliable engine. They have 20mm wrist pins so they will require a set of rods with 20mm pins to match. They feature JE's 2618 alloy which is stronger then most other pistons made from 4032, and are specifically engineered for extreme applications. Dish requires no deburring or preparation.