The usual mask used is 255.255.255.0, where for the 192.168.0.x address range the 192.168.0 is the network address and the .x (what ever number x represents) is the device address.
A mask of 255.255.0.0 would be a network address of 192.168 with device addresses of y.x.
A mask of 255.255.255.248 would give a very restricted device address range of only a couple of usable addresses.
Not to be picky but a mask of 255.255.255.248 allows 6 usable addresses....255.255.255.252 would allow for only a couple (2). A subnet mask is used ONLY by the local host (computer, router, whatever) when it has a IP packet to send - it uses the mask to make it’s one routing decision - (1) does this packet have a destination address for devices on my local network - if so it will “flood” out a query packets to all local devices asking “who has this IP address” or (2) this packet is not meant for anyone on my local network and therefore I will send this packet to may default gateway (typically your router). That is the only purpose for the mask - is a packet that I need to send out my interface local or not).....