This kit contains the three opamps and some passives to convert the Objective2 amplifier to the low power version for an extended battery life
2x - Texas Instruments TLE2062CP (replaces U3 and U4)
1x - Burr Brown OPA2277PA (replaces U1)
all passive parts needed are included as well
this simple change is worth to consider if
a.) you use your Objective2 mainly on battery power and
b.) your headphones have an impedance of 32 Ohms or higher.
More details can be found in NwAvGuy's blog article here