Magnesium with SRTJigsaw magnesium support energy production and healthy muscle function. The "SRT" in Jigsaw Magnesium w SRT stands for Sustained Release Technology, often referred to as "time release", and it's the major difference that gives this product its superior effectiveness. Instead of the magnesium being dumped into your system all at once, SRT slows down the release of magnesium so it's spread out over 8 hours, which allows your body to absorb the maximum