Probably because they’re hard to find/get a hold of. Everyone seems to be carrying the FB4 tint bin. The closest we’ve had to below BBL SST20 so far is the FA3 tint bin in Fireflies’ lights, but those still seem to average out to just above BBL. FB4 isn’t bad - could use a minus green filter but is by no means terrible without one.
Still, hopefully someone can secure FA1 or FA4 tint bin in the near future.
Dont’ know. But I doubt it’s worth it because unless you are a flashlight manufacturer that can design a host around it, I doubt you can make use of it.
I will actively look for these Bins
Simon, hope you did not order a large batch of the SST-20 FB4 tint bin. Once you get some Cree 5D tint emitters and compare it with the SST-20 FB4 tint bin, you will understand why the FB4 is not very good looking.
Until you shine on skin or wood etcetera…
That’s when CRI and R9 values come into play.
Dont worry ,friend,not everyone hates FB4,
and i will add FA1 or FA4 in my store ,i just supply one more choice for buyer
Simon any chance you will consider making the pills out of copper instead of brass for better heat sinking and heat transfer?
I am worried that the copper surface is easily oxidized.
I see no problem with it, copper barely oxidizes at low temperatures. On the other hand, standard rosin flux comes in super handy to remove its oxidation while still hot when hot air soldering or reflowing, for example.
Cheers ^:)
Fri, 01/11/2019 - 08:34
Great to hear Simon, definitely interested in FA1 or FA4 when it becomes available.
I dunno what CRI the XPL HI 5D's are, but wow, the more I look at them and compare to other LED's if one LED to one LED lights or triple to triple, everything else is blahhh. I assume they are in the 70's for CRI - not sure if anyone tested them, but Richard at MtnE and Hank at IOS don't list the CRI for them. XPL-HI's still seem pricey though, where others now are like 1/2 the price.
Almost all the available Cree 5D tint are 70 CRI. I wish they had some 90 CRI version. The E21A 4000k and 219b 4000k 9080 looks similar to Cree 5D tint but with better color rendering and lower output. I suspect the SST20 FA1 tint bin will look about the same as Cree 5A or 5D tint.
Why worry about oxidation when it is not visible? It will not affect thermal performance. I bought a light from Enogear that had a copper pill. It has amazing thermal performance.
In this flashlight the copper has only thermal purpose. But in an S2+ the pill transfers current from body to driver. So oxidation is not good for electrical contacts.
With such a huge contact area, I doubt any oxidation will affect current. I have been using copper triple emitter pills in the S2+ for so long and measured no change in output.
Simple fix too:
Tactical 
forward switch? 
Oxidation is not a problem and is anyway easily solved.
The actual problem for Simon Mao is probably finding a reliable source at a fair price for copper machined parts. We need to admit this may come at a premium pricetag, but it is doable.
Copper is mine! Copper divine! :-D
Cheers ^:)
I’m new to BLF, so I have some questions prior to ordering the S2+ SST20:
From reading posts, it looks like most everyone owns a S2 and if I’m correct its because Simon supports moding by making hosts, reflectors, drivers, etc available at Ali?
Can anyone explain the four color choices — 7135x3, 7153x4, 7135x6, 7135x8?
Is the head glued in finished S2+? I’d like to use this light to learn from, so I want to be able to easily open the head and look at how a driver is installed, etc.
How do I get the 15 percent discount, do I PM Simon here with my order number?
And, final question on a battery for this light, from reading other posts an unprotected NCR18650GA should work great for this light, thoughts?
Hi CMU_84!
Those are not “colour choices” but choices about the driver and the number of 7135 chips you can “have” on the driver. More chips mean more power, more output on top levels (100%), but also more more heat when using the flashlight for longer times.
The head is not glued. Depending on the number of 7135 chips you want in your flashlight’s driver, the driver may be soldered to the pill (6 or 8*7135) or it may be held with a retaining ring (4*7135). So, you can unscrew the pill and de-solder the driver or simply unscrew it to access the driver and start modding 
In your order write a message to the seller saying you’re a BLF member (with username, maybe)!
Yes, but you also have others with high capacity, such as Samsung 35E, Sanyo NCR18650GA .