Matching a specific host

For standard access lists:

Access-List 10 permit 192.168.150.50 0.0.0.0
or
Access-List 10 permit 192.168.150.50 (standard ACL’s assume a 0.0.0.0 mask)
or
Access-List 10 permit host 192.168.150.50

For extended access lists:

Access-list 110 deny ip 192.168.150.50 0.0.0.0 any
or
Access-list 110 deny ip host 192.168.150.50 any