As seen in the Atari Lynx FAQ by Robert Jung

 
Atari Lynx Specifications
Physical dimensions:

Size: 9.25" x 4.25" x 2" (10.75" x 4.25" x 1.5" for original Lynx)

Screen: 3.5" diagonal (3.25" x 1.88" approx.) 

Speaker: 2" diameter 

Buttons: 

Two sets of fire buttons (A and B) 

Two option buttons (OPTION 1 and OPTION 2) 

Pause button 

(OPTION 1 + Pause = Restarts the game OPTION 2 + Pause = Flips the screen, which allows the Lynx controls to be reversed) Power on light (Not on original Lynx; indicates unit is on) 

Power on button Power off button Backlight button (Not on original Lynx; turns off the screen, but does not turn off the game. This saves electricity use when a game is paused) 

Joypad: Eight directional 

Controls: Volume Brightness 

Ports: 

Headphones (mini-DIN 3.5mm stereo; wired for mono on the original Lynx) 

ComLynx (multiple unit communications) 

Power (9V DC, 1 A) 

Game card slot 

Battery holder (six AA)

For the technically minded, the Lynx has two basic chips that form a
cooperative set of co-processing subsystems that maximize the Lynx's
performance by sharing the work of executing a game program. These
chips are called Mikey and Suzy.

Mikey (16-bit custom CMOS chip running at 16MHz)
- MOS 65C02 processor running at up to 4MHz (~3.6MHz average)
8-bit CPU, 16-bit address space
- Sound engine
4 channel sound
8-bit DAC for each channel
(4 channels x 8-bits/channel = 32 bits commonly quoted)
Atari reports the range is "100Hz to above the range of human
hearing"; spectrum analysis shows the range may go as low as 32Hz.
Stereo with panning (mono for original Lynx)
- Video DMA driver for LCD display
4096 color (12-bit) palette
16 simultaneous colors (4 bits) from palette per scanline (more than 16
colors can be displayed by changing palettes after each scanline)
- System timers
- Interrupt controller
- UART (for ComLynx)
- 512 bytes of bootstrap and game-card loading ROM

Suzy (16-bit custom CMOS chip running at 16MHz)
- Blitter (bit-map block transfer) unit
- Graphics engine
Hardware drawing support
Unlimited number of high-speed sprites with collision detection
Hardware high-speed sprite scaling, distortion, and tilting effects
Hardware decoding of compressed sprite data
Hardware clipping and multi-directional scrolling
Variable frame rate (up to 75 frames/second)
160 x 102 "triad" standard resolution (16,320 addressable pixels)
(A triad is three LCD elements: red, green, and blue)
Capability of 480 x 102 artificially high resolution
- Math co-processor
Hardware 16-bit multiply and divide (32-bit answer)
Parallel processing of single multiply or divide instruction

The Lynx contains 64K (half a megabit) of 120ns DRAM. Game cards
currently hold 128K (1 megabit) or 256K (2 megabits) of ROM, but there
is a maximum capacity of up to 2 megabytes (16 megabits) on one game card.
In theory, this limit can be exceeded, either with bank-switching
hardware in the card, or by using a ROM power on/off line as an extra
address line (up to 4 megabytes). Most Lynx game cards are 256K ROMs.
Three games are on 512K ROMs: NINJA GAIDEN 3, PIT FIGHTER, and JIMMY
CONNORS TENNIS, along with the never-released EYE OF THE BEHOLDER.

The first few hundred bytes of the game card is encrypted to prevent
unauthorized developers from writing Lynx software. This scheme was
introduced by Epyx as an effort to enforce game quality.

With alkaline batteries, the reasonable average battery life is 5 hours.
(4 hours with the original Lynx) The Lynx can run off rechargeable
Ni-Cad batteries, but average battery life drops drastically to 1.5 hours
per recharge (1 hour for the original Lynx). Your mileage may vary.