The Microsoft Lumia 950/950XL has a built in call recorder.
http://www.windowscentral.com/enable-native-call-recording-lumia-950
Profanity removed it's not like your recording it for court or police neways.It'd be tricky to use, legally. There's 0, 1, ans 2-party laws that require that # of participants in the call to be informed that the call is being recorded.
http://www.rcfp.org/reporters-recording-guide/state-state-guide