Apple is falling behind rivals when it comes to wearables, those small electronic devices like fitness trackers and smartwatches that are embedded with sensors.

The technology giant’s share in the global wearable market declined over 50% during the second quarter compared to the same period last year, according to the International Data Corporation. Its share of devices shipped fell to 7%, or 1.6 million, from 20.3%, or 3.6 million, the report said.

The steep decline in Apple’s share came as the overall global wearable market grew 26.1% year-over-year with 22.5 million devices shipped. The decline also shows the serious challenges that Apple faces in mastering this emerging market despite its strong position in smartphones and tablet computers.

IDC breaks down the wearable market into two categories—basic and smart wearables.

Get Data Sheet, Fortune’s technology newsletter.

Shipments of basic wearables, including most bare-bones fitness trackers, gained 48.8% year-over-year in the second quarter. Consumers seemed to be drawn by the simplicity of basic wearables, their cheaper prices, and the fact that many companies sell them.

Smart wearables like the Apple Watch, however, are failing to catch on with overall shipments dropping 27.2% in the second quarter, according to IDC. But IDC cautioned that it’s still early and that “vendors are slowly making strides to improve them.”

“Smart wearables, meanwhile, are still struggling to find their place in the market, “Ramon Llamas, IDC’s research manager of wearables, said in a statement. “There is plenty of curiosity about what smart wearables – particularly smartwatches – can do, but they have yet to convince users that they are a must-have item.”

Fitbit fit is the current leader of the wearable market having shipped 5.7 million devices in the second quarter of 2016. Chinese electronics maker Xiomi is the second biggest wearable device shipper, followed by Apple aapl and Switzerland-based technology company Garmin.

Apple’s big annual device showcase event is this Wednesday, leaving many Apple analysts speculating whether the company has any new products to announce that may be a hit with consumers.

For more about Apple, watch:

One such rumored device is a new version of the Apple Watch. Fortune’s Don Reisinger reported that Apple’s online store currently lists almost all of its Apple Watch models as sold out, which may indicate that it’s making room in its stock for a newer version.