How does an ACES suit seal at the feet?

Question

The Advanced Crew Escape Suit -- also known as the ACES suit or "pumpkin suit" -- was worn by all Shuttle astronauts (since 1998) during launch and landing.

The helmet and gloves were connected to the suit by locking rings. Leather paratrooper boots were worn on the feet. How did the suit seal at the feet, to maintain suit pressure?

I can imagine several possible solutions (in order of increasing skepticism):

• The suit material extended to completely cover the foot, and slipped inside the boots.
• An elastic or inflatable cuff that slips inside the boot.
• An elastic or inflatable cuff that covers the outside of the boot.
• A locking ring to the boot.
• There was no seal.

Answer 1

Despite the fact that the ACES "pumpkin suit" is one of the coolest suits ever to exist, I must expose the shocking truth: it was basically a "footie suit".

(kytebaby.com)

In other words, the feet/socks of the suit were connected to the legs, as you can see in this picture of the STS-135 crew in training:

(annotation mine)

The Crew Escape System training manual has a wealth of info on ACES and discloses the pressure interfaces:

Six pressure seals:

1. Helmet visor

2. Neck dam

3. Main suit zipper

4. Bioinstrumentation Passthrough (BIP) plug

5. Right glove

6. Left glove

Note no "sock" interface.

The blue undergarments are for cooling and are laced with tubes which carry coolant water.

Each crewmember is provided with a cooling system. There are two models that utilize thermal electric modules for suit cooling: Individual Cooling Units (ICUs) and Thermal Electric Liquid Cooling Units (TELCUs), also known as “two-person cooling units.”

The two main components of the TELCU/ICU cooling system are:

a. The TELCU/ICU that cools the water flowing through the network of vinyl tubing in the Liquid Cooling Garment (LCG).

b. The two-piece LCG worn by crewmembers as an undergarment.

Here is a closeup snippet of the picture above showing the cooling tubes in the undergarment.