My commuter's twenty year old Overland saddle wedge is wearing out, so I'm looking for an aero saddle wedge large enough for tool, a rain jacket, spare tube, small cable lock, etc. But not some big boxy bag that chafes my legs. I would prefer something waterproof, but that isn't essential.

Suggestions?

undetectable extension charm?

You might want to check out what the Banjo Brothers have. They have a saddle trunk bag that is waterproof.

How are you supposed to use those bungee if you have a fender mounted?

I am seriously liking the Banjo Brothers bag.

They mention an adapter, From the site:
If you do not have bottom braze-ons, order the Mountain Wedge 3 Adaptors that wrap around the chain-stays
I would think that would work.

I like the Banjo Brothers one better though.

On edit: that jandd is really huge. Beats the Ortlieb, but it might be too big for some people

The biggest Ortlieb saddle bag is huge. I know a number of randonneurs that use it in lieu of a handlebar bag or a carradice saddlebag.

The closing mechanism is a little weird. It almost is an open bag with a strap across the back. Leave enough of the bag loose that you can overlap the sides of the bag. You twist one of the two straps up, and the other down. If you twist them both in the same direction, they can unwind and you will lose everything in the bag.

I can't tell from their site, is it the same width from front to back, or does it taper narrower at the front?
That's the main complaint I have with many larger bags, the front is wide enough that my legs hit the bag on every pedal stoke.

There's these bags https://www.klickfix.de/index.php?lang=en

The site says the Contour, waterproof is scheduled for release soon.

QR clip is a band on the seatpost, so fits any saddle..

Carradice SQR another rear bag long but narrow behind the saddle

https://www.wiggle.co.uk/us/carradice...g-sqr-bracket/

so leg contact not a problem

I've never actually seen or used the product, so I'm not sure either. But if you are concerned about your legs rubbing the bag (and your cargo isn't more than 5 lbs.) maybe something like the Hi-Tails from Detours would work better.

That would certainly provide leg clearance, but I don't think it would work with my rear rack. My saddle isn't high enough above the top of the rack for those.

So far the Ortlieb looks like the best bet -- tapered narrow in front, large enough, I think, and waterproof.

As near as I can tell the Jandd mountain III seat bag is the largest, other than the Carradice Camper long flap, whidh the OP stated that he did not want.
I, on the other hand, would love to score a Camper longflap, maybe for my birthday.

Waterproof and 13x20x11 cm:

https://www.ebikestop.com/pacific_out...ome-BG3210.php

I use one on my commuter - 2 700x32 spare tubes, 2-3 CO2 cartridges and inflator, multi-tool. All with room to spare for lots of other stuff.