# Form - Lead Field - Core Number
**URL:** https://forum.mautic.org/t/form-lead-field-core-number/5831
**Category:** Product Support
**Created:** [February 18, 2016, 8:27pm UTC](https://forum.mautic.org/t/form-lead-field-core-number/5831 "2016-02-18T20:27:29Z")
**Posts on this page:** 2
**Page:** 1
### Author:  [@bluestar](https://forum.mautic.org/u/bluestar)
#### Post date: [February 18, 2016, 8:27pm UTC](https://forum.mautic.org/t/form-lead-field-core-number/5831/1 "2016-02-18T20:27:29Z")
I have a number of forms to generate lead details, including their contact number using the core number option. Potential leads are inserting an email ID here instead of a contact number and are able to submit the form. Is there an option that prevents this and only allows numbers and the + sign please?
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### Author:  [@bluestar](https://forum.mautic.org/u/bluestar)
#### Post date: [February 18, 2016, 8:27pm UTC](https://forum.mautic.org/t/form-lead-field-core-number/5831/2 "2016-02-18T20:27:29Z")
I have a number of forms to generate lead details, including their contact number using the core number option. Potential leads are inserting an email ID here instead of a contact number and are able to submit the form. Is there an option that prevents this and only allows numbers and the + sign please?