This is tweeter (high frequency speaker) crossover which will filter the treble (high frequency) to be feed to tweeter. The bass (low frequency) cannot pass the tweeter speaker since there is low pass filter made of C1, C2 and R1 assembled before the tweeter.
The tweeter can be a 2 to 3 inch, 4 to 8 Ohm one .
R1 is used to adjust match the the tweeters output level to that of woofer.
Make Your Own Printed Circuit Boards
Make a PCB in very easy steps..! Create your PCB design using PCB designer software like Eagle, print out your design on photo paper or glossy paper with laserjet printer. Stick the printed design on the PCB (copper side) and then heat it using hot iron plate. The ink will stick on the PCB and it will be ready for etching process. Watch this video detailed steps:
Note: If you don't have laserjet printer, then you can print the design on standard paper. Copy the printed design at Copy Service around your location (with glossy paper).