> ## Documentation Index > Fetch the complete documentation index at: https://docs.zeotap.com/llms.txt > Use this file to discover all available pages before exploring further. # How to Stitch Unknown to Known Profile using the Custom Strategy > As per the nature of unknown or anonymous interaction, the identifier that is received or tracked is always of low fidelity. If these low-fidelity identifiers are marked as Secondary, then they do not unify with a known or high-fidelity identifiers’ profile. If you want to unify these anonymous profiles with a known identity, then you have to even consider low fidelity IDs in the Primary classification. This setting itself starts unifying the profiles with high-fidelity-based customer profiles. However, we recommend that you keep these low-fidelity identifiers at the lowest priority when compared to the other high-fidelity identifier in the Primary classification. Based on this setting, this ID will participate in identity resolution and unification only in the absence of other higher-fidelity identifiers. | **IDENTIFIER** | **CLASSIFICATION** | **PRIORITY** | **NO. OF ID TO STORE PER PROFILE** | | :------------- | :----------------- | :----------- | :--------------------------------- | | `User ID` | Primary | 1 | 1 | | `Email` | Primary | 2 | 1 | | `Cellphone` | Primary | 2 | 1 | | `GA Client ID` | Primary | 3 | 5 | | `Maid` | Secondary | 1 | 5 | | `CCode` | Disabled | | | | **USE CASE** | **DATA RECORD** | **WHAT DOES ZEOTAP DO?** | **PROFILE CREATED** | **NOTES** | | :-------------------------------------------------------------------- | :----------------------------------------------------------------------------- | :-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | :-------------------------------------------------------------------------------- | :------------------------------------------------------------------------------------------------------------------------------------------------- | | A profile of User A is shared from their Brand's CRM | `Mobile: C1`

`Email: E1` |

  1. In this record, there are two Primary IDs and both are of the same priority.

  2. Hence, both IDs are used for ID resolution (lookup).

  3. For C1, the match found is Z3 and for E1 the match found is profile Z1.

  4. In this case, the profile with the first created UCID, that is, Z1 is retained as the master profileand the other matched profile, that is Z3 is merged to it.
| `Z1 {User ID: U1Email: E1Mobile: C1Maid: M2, M1GA Client ID: G1}` | This use case showcases how the system performs ID resolution and unification if a record contains the same priority ID within the classification. | | User A navigates to the brand’s website and logs in | `User ID: U1`

`GA Client ID - G1`

`Adobe cookie: A1` |

  1. In this record, there are two Primary IDs, U1  is defined as Priority 1 and G1 is assigned Priority 3.

  2. The ID resolution happens using U1 and G1 is used for reconciliation of any record, where G1 is the highest ID in that profile.

  3. For U1 and G1 the match found is Z3. Hence, the Z3 profile is updated

| `Z3 {User ID: U1Email: E1Mobile: C1Maid: M2, M1GA Client ID: G1Adobe Cookie: A1}` | | | User A navigates to thebrand’s websiteanonymously(without logging in) | `GA Client ID: G1`

`TTD Cookie: T1` |

  1. Here, we have receiveddata against aPrimary identifierGA client ID.

  2. Considering that this isthe only Primary identifierin the record,the system finds Z3(Primary id based profile)as a match for this ID andupdates the datafor this profile.

| | |