This book goes through the possible reasons for unemployed skilled people when there are business shortages. Prof Capelli reflects my opinion that it is mostly down to businesses, not the candidates - but he has facts where I have opinions.
I may have received a duff one, but the bell would only ring if there was nothing but air between the bell push and the ringer. Significantly worse performance than the old Micromark system I wanted to replace.
On the other hand the supplier was easy to work with and refunded without any hassle.