"specify your" is a correct and usable phrase in written English.
You can use it when you want to prompt someone to be specific. For example, "Please specify your preferred choice from the list."
Some Passbook-enabled apps let you specify your preferred store locations within their settings.
Be sure to specify your bike size in the Notes section of the reservation form.
Please specify your gift to go to the computer science department, in memory of Steven A. Gold.
The minimum order is one square metre, and you can specify your colour, as well as shape and size.
If you are one of five doctors tending a patient, it can be tricky to specify your personal responsibility.
Your first two novels were set in Pakistan, yet you never specify your protagonist's homeland in this case.
Specify your favoured house at Hogwarts, and give it your Pottermore login details (if appropriate) and the preamble is done.
International wines are moderately priced, but specify your choice of vodka or they'll hit you with a Grey Goose.
These are still as relevant and interesting to a potential employer and there's no reason to specify your family connections on your CV.
In case you disagree with all proposals that are being made, you may specify your own tax scheme.
Once you have an account, you can create a profile to specify your job-search preferences.
