Green House has started selling the GH-SMTF, a 29 mm Bluetooth tracker that rides on Google's Find Hub network. 4 Reviews ← exclude selected types ← exclude selected tagsGreen House began selling the GH-SMTF series in Japan in early August. It is an Android-only tracking tag built around Google's Find Hub network. It measures 29 mm across and 8.6 mm thick, weighs about 7 grams with the cell fitted, and ships with a carabiner keyring. The newer tag is smaller but costs 380 yen more, and Green House has not said what the premium buys — the specifications are otherwise identical.