The ESD Association‘s Resistance-to-Ground (Rtg) requirement for an operator wearing a wrist strap is < 3.5 X 107 ohms (ANSI/ESD S20.20). A wireless wrist strap will never meet this requirement.
Wireless wrist straps claim to work by “making (a) body’s static electricity to discharge through discharge box.” Assuming that an operator was tribocharged to 10 KiloVolt and wearing the “wireless” wrist strap, it would take hours or days even depending on the ambient relative humidity to get you below 5 KiloVolt, never the less 10 Volts. Most (if not all) of the charge reduction on the person would be due to natural recombination of the charges on the person’s skin, not the “wireless” wrist strap. For more info the ESD Journal explores the the myth of the wireless wrist strap HERE.