Website: https://plickers.com/
Free iPhone app: https://itunes.apple.com/us/app/plickers/id701184049?mt=8&uo=4&at=10l6SU
Free Android Phone app: https://play.google.com/store/apps/details?id=com.plickers.client.android
Free Android Phone app: https://play.google.com/store/apps/details?id=com.socrative.student
Free iPad app: https://itunes.apple.com/app/student-clicker-socrative/id477618130?mt=8&uo=4&at=10l6SU
Free iPhone app: https://itunes.apple.com/app/student-clicker-socrative/id477618130?mt=8&uo=4&at=10l6SU
Website: http://www.socrative.com/
Edmodo app: http://www.edmodo.com/publisher/socrative
Google Chrome app: https://chrome.google.com/webstore/detail/socrative-student/nblhpecglllndfihipmpdoikimcmgkha
Website: http://polldaddy.com/
Free iPhone app: https://itunes.apple.com/us/app/polldaddy/id376413866?mt=8&uo=4&at=10l6SU
Free iPad app: https://itunes.apple.com/us/app/polldaddy/id376413866?mt=8&uo=4&at=10l6SU
Website: http://www.iclicker.com/
Free Android Phone app: https://play.google.com/store/apps/details?id=com.appficient.iclicker
Free Mac program: http://www.iclicker.com/support/downloads/
Free Windows program: http://www.iclicker.com/support/downloads/
Physical product: http://www1.iclicker.com/purchase-response-devices