A PTR record, also referred to as a Reverse IP record, is an "A" record in reverse. In the case of an "A" record, DNS lists a Fully Qualified Domain such as www.foo.com and points it to an IP address. A PTR record lists an IP address and points it to a Fully Qualified Domain such as www.foo.com.
Unlike domain names, IP space used by Spectrum Business is owned by Spectrum Business. Spectrum Business assigns the client the right to use certain blocks of space, which are assigned during the account creation process. The client may choose DNS service providers, including Spectrum Business, a third-party DNS service provider, or the client may manage their own DNS services. IP addresses, however, may only be managed by the owner of the IP space, which is Spectrum Business.
In order to enter PTR records into the Spectrum Business DNS server, the IP space must be Spectrum Business Commercial owned IP space. This means that it is the IP space is assigned to the client by Spectrum Business for their use only.