What is the difference between standard J-Cups and roller J-cups

What is the difference between standard J-Cups and roller J-cups for a squat rack? - Quora

What is the difference between standard J-Cups and roller J-cups for a squat rack? - Quora

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What is the difference between standard J-Cups and roller J-cups

Which is the best foldable squat rack in India? - Quora

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