Rubber booster Lifefit Expander Circle Multi-purpose booster LIFEFIT EXPANDER CIRCLE for strengthening the muscles of the upper and lower limbs. The booster rope is made of durable and extra flexible silicone material and has soft non-slip grips on the ends. Due to the low price and high efficiency of the exercises, the LIFEFIT EXPANDER CIRCLE is a popular tool for home training. - special strengthening rubber in the shape of a circle - soft foam non-slip handles - suitable for all-round home strengthening.