1. What they are
The CR14250 is 14.5 mm across and 25 mm long, and the CR14505 is the same width but 50.5 mm long, the length of a normal AA. Both are 3-volt lithium cells, holding about 650 mAh and 1400 mAh.
2. Why the extra volt matters
A device built for 1.5 volts gets 3 volts here. Some will run it happily, some will be damaged by it, and a lot of them will simply sit there and do nothing.
3. Where they are used
Utility meters, industrial memory backup and some older equipment run on them. They also turn up as replacements for AA cells in gear that was designed around them from the start.
4. They are not lithium AAs
A lithium AA, sold as an L91 or an FR6, gives 1.5 volts, the same as alkaline, and is a proper drop-in replacement. The 3-volt cells are a different thing entirely.
5. How to tell them apart
Read the code. If it starts with CR14 it is a 3-volt lithium cell; if it starts with L91 or FR6 it is a 1.5-volt lithium cell that replaces an alkaline AA.