The advantage of the L-eXtreme filter is that there is no transmission between the H-beta and OIII lines, as there is no nebula emission lines there. In this case, it isn't letting light pollution come through so that maximize nebulas signal and make the sky background darker while imaging. The L-eXtreme filter should better isolate the emission lines only and better protect from light pollution.

EOS Clip version of the famous L-eNhance filter by Optolong

Optolong L-eNhance is a dual-band pass filter which has been designed for DSLR (digital SLR), color CMOS and monochrome CCD cameras. The convenience and cost effectiveness of this filter allows amateurs to image a rich selection of astronomical images, even in bright, heavily light-polluted areas. It effectively isolates the H-Alpha, H-Beta, and Oxygen III nebula emission lines and achieves a maximum transmission of up to 90%. The performance of this filter delivers superb images.

L-eNhance 2" Optolong filter (M28x0.75) 50.8mm - Recommended for: shooting in double pass band (H-Alpha, OIII and H-Beta) with CMOS or CCD color cameras or DSLR

L-eNhance 1.25 "Optolong filter (M28x0.75) 31.8mm - Recommended for: shooting in double pass band (H-Alpha, OIII and H-Beta) with CMOS or CCD color cameras or DSLR