If turned on, whenever you delete a previously synced contact, this app will attempt to delete the same contact from either Gmail or Mac during the next sync.
If you want to sync your contact photos, turn on the "Sync Photos" checkbox.
Filter Sync By Groups
By turning on the filter by groups switch, you will have the opportunity to select which groups are synced.
Ignore "Other Contacts" in Gmail
In Gmail, contacts that don't belong to any groups including "My Contacts" go into the "Other Contacts" category. If you don't want the contacts in the "Other Contacts" category to appear on your phone, you should enable this option.
Merge Contacts (2-Way)
With this setting turned on, during 2-way syncs, the contents of matching contacts will be merged when necessary (for example, during the initial sync).
Merge Contacts (1-Way)
With this setting turned on, during 1-way syncs, the contents of matching contacts will be merged rather than one contact replacing the contents of the other.
Sync Postal Country Codes
If turned on, postal country codes will be synced. As a result, international postal codes will be formatted correctly.
Batch Gmail Updates
If turned on, your Gmail contact updates will be batched in groups of 100 when sent to Google. Doing so results in faster syncs. However, if you happen to have a problem with several of your Gmail contacts not getting updated, you can turn off "Batch Gmail Updates" as it may help you identify the problematic contact. Please email support for more information.