A Teensy 3.6 can be purchased both with and without header pins already attached. Buy the one with pins.
B Each LM358 contains two separate op-amps. Other op-amps would also work, but make sure you buy enough: you’ll need at least five.
C This is a resistor assortment pack. It’s convenient if a bit wasteful. These are fairly ordinary resistors; substituting resistors you happen to have in your lab will probably work fine.
D Same comment as for C, but with the word “capacitor” substituted for “resistor.”
E This is a full-size solderless breadboard. You can also put the system together on a solder-able breadboard or a perf board.
F This adapter has pins that fit snugly into the breadboard, but you can use any kind of barrel adapter.
G An assortment pack of wire to connect things. You can use 22 AWG solid core wire instead.
H This particular adapter has a positive outer shell and a negative inner pin. Other wall adapters have the opposite polarity. Make sure you know which you have before connecting anything else.
I The connectors offer a simple, inexpensive way to connect the system to the BNC ports of typical DAQ boards and patch clamp amplifiers.
J This is a standard and widely-used rail splitter IC.
K This cable connects the Teensy 3.6, which has a 5-pin Micro B USB input, to the USB port of a computer.