You want argue with the price, but the tolerances vary, they are supposed to be 20mm dia and 3.2mm depth hence the name. But I found the depth on some was as low as 2.8mm making it a loose fit and therefore unreliable connection in a standard holder. Also the voltages varied from around 2.8v to 3.5volts. So choose the ones that are around 3.3v unloaded and bend the holder to fit if need be. But if it's for something important maybe better to go for a well known brand at normal price.
CEM3340 VCO Integrated Circuit - New - Voltage Controlled Oscillator Chip
12 Apr, 2018
A great find!
The VCO worked as it should, lucky to find another a new, albeit temporary source.