Before the Office of the Telecommunications Authority (Ofta) opened some of its frequency bands for free use by the public, walkie-talkies were used mostly for commercial purposes. The cost was prohibitive for most citizens, with a radio licence priced at $300 per year. With a licence, a user was assigned a frequency to use, determined by their industry. Commercial radios cost between $1,000 and $4,000, operate on 5 watts and can be used within a radius of 5 to 6km. Devices designed to operate on the 409 and 410 frequency bands - made freely available to the public this year - are limited to 0.5 watts. Commercial walkie-talkies are still on the market, selling for use by workers such as van drivers and security guards. But some companies are switching to the free bandwidths. Chain stores such as Giordano, Esprit and Pizza Hut have abandoned licensed frequencies to save costs. Eric Lee Kam-chung, a salesman at radio shop CA Sheimer, said his store sold about 400 sets a month. Most of the buyers are those chain stores, restaurants and some schools. A minority of his customers are individuals who buy the radios for personal use. 'These companies don't need the long distance service, so they are switching to cut costs,' he said. The authority does not require manufacturers to obtain certifications on the radios for the 409 and 410 frequencies as long as they do not surpass the 0.5 watt limit. A voluntary scheme exists for manufacturers to have their products examined and certified by Ofta. Once they meet the standards and are certified, the authority issues stickers for them. But an Ofta spokeswoman noted that products without stickers have not necessarily failed to meet the standard.