Dharaṇendra yantra is a Jain devotional diagram associated with Dharaṇendra, the serpent deity who is especially connected with Lord Parshvanath. It is used in some Jain traditions as a protective and worshipful yantra, mainly for devotion, remembrance, and seeking spiritual protection. ( jainknowledge.com)

In Jain understanding, such yantras are traditional ritual aids in some lineages, but they are not universally central or canonical for all Jain practice. The core Jain path still remains Right Faith, Right Knowledge, and Right Conduct, along with devotion to the Tirthankars. ( jainknowledge.com)

If you want, I can also explain:

• the meaning of Dharaṇendra, or
• the use of Dharaṇendra yantra in Jain worship.