Yes one is a clear UV filter then you get the ND 8 , 16 , 32 and 64 , l mostly use the 8 and 16 as I shoot mainly early morning and late evening...
Unusual to find those ND # combos, most lug you with a 4 as standard, and most don't include a 64.
My NiSi 6 set also has the ND8,16,32, and 64, plus UV clear and clear polariser.
I used my NiSi ND16 the other day at the beach, it was late in the day, left it on right through to sunset . . . usually I would use an ND8 but just I thought I'd give the 16 a go.
Was surprisingly good and not too dark.
Kinda glad the 6 set I have doesn't include the ND4, as the UVCL and C-PL are both around 1.5 stops anyway.
Reading thread here it seems my 6 set was way more than Neewer, but I feel worth it for the flexibility, and NiSi has a good reputation / background in regular photography filters.
I will definitely add Neewer to my recommendations to others looking for a more budget option, their filters look to tick most of the boxes on quality.