Don't know if it works yet, but I paid less than $5 for it. Bargain find or total trash? It's smalllll.















And... I went ahead and painted the blue bit silver. Good idea? Bad idea? I just know that silver paint smelled awful.





Here's me and my shaky hands showing that the LEDs still show.

Hi there, Nice find.... and yes this model is one of the smallest measured. Mine is a bit more beat up than yours. Its great reading here is link includes pictures of all measured Walkman too.
WORLDS SMALLEST WALKMAN competition

The RQ-SX72 was the 6th smallest walkman.. very impressive ranking indeed. Here is copy of results for follow up post putting all the results together.

Follow up Final Results smallest walkman

RANKING OF SMALLEST WALKMANS

cm3
1. Sanyo JJ-P4 / JJP5 135.58 JohnEdward/AGENTORANGE
2. Sony WM-701C 137.75 JohnEdward
3. Kenwood CP-3X 142.14 Skippy1969
4. Sony WM-EX20 146.21 JohnEdward Thinnest 17mm
5. Panasonic RQ-SX71 146.61 JohnEdward
6. Panasonic RQ-SX72 149.86 JohnEdward
7. Panasonic RQ-SX91 151.34 JohnEdward
8. Sony WM-10 w/tape 155.50 JohnEdward
9. Sharp JC-K99 156.22 AO/Jazzrat2000
10. Sony WM-150 156.85 JohnEdward
11. Sony WM-701/702 157.17 AutoReverser
12. Sony WM-102 157.62 MRP32Dave
13. Sanyo JJ-F4 158.76 JohnEdward
14. Aiwa HS-PX610 160.18 JohnEdward
15. Sony WM-808 163.40 JohnEdward
16. Sony WM-EX1 167.15 JohnEdward
17. Sony WM-FX511 168 A.A.Fussy
18. Sony WM-WE01 169.54 JohnEdward
19. Sony WM-F100III 172.49 JohnEdward
20. Panasonic RQ-S44 173.22 JohnEdward
21. Sanyo ESP-7 174.18 AO Thinnest 17mm ties EX-20
22. Hitachi CP-88R 174.84 Walkgirl
23. Toshiba KT-AS10 185.64 ZX280
24. Panasonic RQ-S75 190.03 JohnEdward
25. Kenwood CP-C7 196.8 Rerooted
26. Sony WM-10RV w/tape 210.75 JohnEdward.

You had asked in the final result topic about if AA battery was included in measurements.

I believe only 4 models out of 26 smallest walkmans used a single AA battery . All measurements had to include the add on battery case if internal area not built in. Amazing is the WM-10 With battery AND CASSETTE in place so unit expanded still ranked in top 10 smallest. The AA battery generally adds to much space as clearly the 22 other units all use the gumstick battery which is less than half volume of round ( wasted space geometric shape) AA battery.

By the way really excellent clear and focused up close pictures..... We all on the forum really appreciate the time and effort to take and put up great photos. WE SO LOVE LOOKING AT WALKMANS right guys and girls :-)