This Sigh Rebus #725

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Do you need a little help? Click to reveal a clue to the above Rebus.
Here is a clue to help decipher the hidden meaning. To test something or to think about an idea in order to decide whether it works or whether you can use it.
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Three [Tri] “This” words with Four “Sigh” words, to give the answer: Try This Four Size.