This article is for introduction of Type A &Type B& A+B
Plug and play/ballast compatible(UL type A)
works directly with the existing fluorescent ballast, so there is no rewiring nor ballast change required.
Advantages：Easy installation for existed fluorescent fixture; No electrical labor cost at the beginning;
Disadvantages: When ballast is broken, you need to replace a new ballast;
Hard to compatible with thouands of models ballasts;
Overall energy cost is higher than rewiring the ballast, LED tube is able lighting without ballast.
2. Ballast-bypass/ direct wire (UL type B)
require to remove or short-cut the original fluorescent ballast.
Advantages: Strictly LED tube lighting, no need ballast; Save energy; More safe with one end powered; Good choice for new projects;
Disadvantages: Labor cost for electrician.
3.Hybrid (UL type A & B)
able to work both as a plug and play with the existing ballast and, once the ballast is broken, you can remove it and have the lamp run off of line voltage.
Advantages: Able to lighting with ballast and without ballast;
Disadvantages: More expensive.
Which one is better? It is depend on your situation.
If it is for new projects, Type B bypass ballast is recommended;
If it is for old lamp replacement, if you don't want to do electrical work later and prefer to real LED lighting low energy cost, type B is okay;
If you want easy installation and think your ballast will not run out in a short time, type A is good for you; If you would like to have easy installation now and take consideration of you don't mind to rewire ballast later, A+B is good for you.
Thanks for your review, if you have more questions, welcome to send email to me for solution.