The spark plug fits into fz25 bs6 model(bought in 2021) perfectly and delivers bit higher low end performance as expected. Although I don't see any considerable mileage improvements, I can definately feel the engine is running smoother.
Excellent quality.
Improvement needed in delivery time
Drag race between V4 Blue (Air filter & Free Flow exhaust) vs V4M (Only sparkplug changed everything else stock, heavier rider with 2kg crash guard) and it clearly shows the One with ₹830 upgrade (R15M) is faster than ₹4700 upgrade (R15 V4 Blue)... The V4 Blue even had a better launch than R15M, but the M caught up after 3rd gear
Original chain and sprocket lasted about 18500 km for me then I installed brass chain and currently I'm at 53000 km that means brass chain got me about 35000 km and still it'll go 5000 km more. So total 40000 on brass chain. Regular maintenance is must.
