It's fast, classic metal from Sweden with clean female vocals. In places, where the tempo is slower, it does sound a little stoner, but it's never long before things liven up again.
On listening again, that last album, Exterminator (2017), is excellent. It's not an 'unsigned' release, because unsurprisingly Night Viper appear to have a deal (Listenable Records).
An even nicer surprise was that they have an earlier album (2015) which does appear to be independent. It's as good as the 2017 album and the best news of all is that it's available on Bandcamp for a mere 3 Euro (or more), which is almost a steal. Go buy both albums and support this excellent band.
I'm not sure why female-fronted bands have been floating my boat recently (Spiders, Amorettes, Substratum). I can't say that I prefer male or female, but it's just what's been coming out and sounding fantastic.
