What does Tymit mean by '3 months interest free'?

We offer our customers the ability to split their purchases into instalments and pay for them over time.  

If you choose a 3-month instalment plan, we don’t charge any interest.  

However, we don’t automatically choose a 3-month plan for you. You may prefer a longer repayment plan. The choice is yours.  

The important thing to remember is that you have to choose your own instalment plan for each purchase in the app.