The most frequently available devices are walking canes and talking watch.
In the sentence, Is it correct If I mention two devices even though I use "the most frequent"?
OR I should mention only one device. In the same way, lest frequently available devices color detector, electronic cane, liquid sensor.
There are a couple of answers to this question:
If the canes and the watches are available and/or used in roughly equal quantities, then suraj is correct in that "watch" needs to be plural.
If using multiple canes with a single watch, or multiple canes but only one watch is available, then you'd need to restructure the sentence:
A talking watch and walking canes are the more frequently available devices.
In this way, you can reference a single item and a group of items at the same time.
