OK, got "Hoops":http://scbhooper.com an S-720i, but now we need the power output kit. These are harder to find at a discount. Here are some sources listed in order of my confidence in them:
* "Colorado Cyclist":http://www.coloradocyclist.com/common/products/productdisplay2_v2.cfm?PRRFNBR=27091&S=22977,22978,27734,20070,22854,28682,12111,24608,24609,27091,24610,24604,16241,24603,12150. $314 vs list of$349.
* "Excel Sports":http://www.excelsports.com/new.asp?page=8&major=3&minor=2&description=S%2D710+Power+Sensor+Set&vendorCode=POLAR. At the $350 list. These are listed in google page rank order: * "Polar-USA.com":http://www.polar-usa.com/new-polar-power-kit.html.$315 but includes free shipping.
* "Trisports.com":http://www.trisports.com/polarpowerkit.html. $297. I've also ordered before from them. * "Polar-Hearate-Monitors.com":http://www.polar-heartrate-monitors.com/polar_power_kits.htm.$315
* Polar Power Output Kit for S-710 Heart Rate Monitor. Another site that has it for \$315.