Dammnit Simon! Stop spoiling us with new lights! 
Regarding “BD”, may or may not be related, but maybe it stands for BeiDou (which refers to “Big Dipper”)? (I seem to recall reading some earlier flashlights that use this brand?)
I understand it well. 2xAA with good cells can sit in a car all winter or summer in our extremes. I would not leave an 18650 light in the console when the internal temps reach 135 or - 15F.
Yes, li-ions lose capacity in negative temperatures but alkalines leak, even Duracell and GP. Discharged li-ion can be usable after 5-10 minutes (if it has built-in charging, you can charge it in the car), but leaked alkalines usually destroy everything they come in contact with, and driver cannot be changed in 10 minutes.
Charging cold Li-ion batteries damages them and may be dangerous. Using them in the cold is fine, though like most batteries, performance and capacity are reduced.
Lithium primaries are the go-to for shelf stability, but Li-ion handles the temperature range the interior of a parked car will experience in most climates well enough.
I use LSD NiMh and keep primary lithiums with them. I has 1 30q that swelled in August heat 2 summers ago, cars are worth more than lumens to me.
Me too, for the earthquake stash/any emergency.
And for the emergency stash, the orange color is just right.
Another light to add to the collection 
I’m excited about the T4, planning to buy as a back up light.
I keep a 2xAA light in my car with a pack of 4 Alkaline cells, stored outside the light so no leak issues.
I like the 2AA form factor, it’s old school. Sharing reflectors and optics with the S2+ is excellent. The only problem is the UI. I’d rather not have mode memory. 4 modes is fine, but the ability to toggle memory on/off would be perfect.
Yes a pen light, is it in your plans?
i have pen light before, but quality is normal.
what about titanium alloy pen light with high CRI LED?
Simon bro, T4 in orange looks real nice.
Sorry, The host is produced as a complete kit. I cannot sell a single part of it.
Simon, I have a random curiosity question. How did you choose the name Convoy for your business?
Great question! I am also curious.
Because its “rockin through the night” :sunglasses:
WOW!!!
*Short answer: That would be awesome! I'd love to continue this discussion. Please be patient and read on when you have time
Not so short answer: Thank you for always listening and answering us, this is the very reason I bought my first Convoy, this relationship between the brand and us makes every light that more meaningful and I'm happy to support Convoy and use the T2 every day. I remember you took the time to help me when I had just discovered BLF as I was looking for a good flashlight to use in the job. I contacted you through AliExpress, at the time T2 didn't have 219B so you recommended 219C.
When you say: "but quality is normal" I think you partially understood your customers. We really want something more, but it's not always the most expensive or the most lumens or candelas, it's the story it tells. My theory is that we buy what makes us happy, and numbers will always be meaningless after some time, but a good story will never go out of fashion, I believe special editions made of titanium should come after the light already have a great story behind it and for that a special place in our hearts, so my suggestion would be for now save titanium for a commemorative version of the lights that made Convoy special, something like the S2 in titanium or S2+ or any light that already made history and for that deserves a special edition.
I suggest that a new penlight has to have a special story first so perhaps we could start one here in BLF with the input of the potential clients?
atomix just started a thread about the perfect medical penlight if you have the time.
https://budgetlightforum.com/t/-/59397
PS: Many brands try to create a storyline with some success but most of the time it sounds artificial because it has no substance, no real people behind it, just marketing material
Price for T4?