Instruction: Extract information from the supporting document to answer the given question.

Input:
Question: Can we mount filters on it?  I dont see the lens having a thread.  Please help. Thanks
Document: I give it 4 stars only because, like all kit zooms, it's a compromise - but a VERY competent one that's likely to please you, and all who see its images.
Well, thanks to the optical stabilization in this lens, you can. I uploaded a sample image of mountaineer-photographer Ed Webster at a book signing (you can buy it on Amazon), and as you will see, the image is SO SHARP you can read the manufacturer's branding on the inside right (your left!) earpiece of his reading glasses.
The 16-50mm lens has no sun-shield hood and takes 40.5mm filters; the 18-55mm lens does have a sun-shield hood and takes 49mm filters. The 16-50mm lens is 9/16" shorter, 2/75oz lighter, and has a power zoom useful when shooting movies. For these reasons, I kept the Selp1650 zoom lens and sold my 18-50mm lens.
This lens fills an important gap in Sony's e mount selection, and is really what makes a nex camera worth the investment. It lives up to expectations and is an excellent lens with some caveats.I got a c3 with the standard 1855 kit lens and soon grew tired of the size and weight of the lens compared to the camera despite the nice metal finish.
So far I can't see much of a difference in sharpness in my old lens and this one which for relativity cheap lens is very good. There is slight barrel distortion after the in camera adjustment but at 16mm and should be expected. (If NEX 7 version is 1.0 or lower must get firmware upgrade before using lens). Over all pleased with lens just wished it was advertised as gray market and no rear lens cover come on!
My video work has appeared on CBS Sunday Morning, local TV and many medical web sites; my stills have been on the business and feature pages of magazines and newspapers worldwide. I bought my NEX-6 to use my languishing Leica M mount lenses, and they are spectacular on the NEX-6. I bought the 16-50 with my NEX-6 because it was cheap when the combination was selling at $200 less than it is today.Now, for this lens.
I've had relatively good success with kit lenses, knowing not to expect stellar performance. But the Sony E-mount 16-50 Power Zoom was very disappointing. I used it on a Sony NEX-6.I liked using the lens, it's small, light and very convenient. But that's where it ended for me. At (and near) the wide end it appears the correction for the severe distortion causes very poor resolution away from the center of the image.
The built quality is very nice with black metal exterior and internal metal mount, and a great look that complements the nex design line well. The combined zoom and focus ring works quickly and effectively after a short period of getting used to.Pictures in the 30 to 50 mm range are as sharp as is reasonable to expect - in my view, very sharp and clearly sharper than the 1855 - BUT as others have noted there is an important issue at low focal lengths where barrel distortion and vignetting become extreme.
If this lens didn't come with your Nex camera then I would highly recommend you adding this to your collection.
This lens is more compact than the kit lens and produces very satisfactory results. I like it a whole lot!
Answer: yes,  40.5mm.