OBSF-24-K

1. Overview

The Sanwa Denshi OBSF-24-K is a 24mm snap-in pushbutton in black ("K" = kuro, Japanese for black), part of the flagship OBSF line manufactured by Sanwa Denshi (Japan). "OBSF" denotes the snap-in flat-plunger design with dual plastic side clips, and "24" indicates the 24mm mounting hole — the compact sibling of the 30mm OBSF-30 action button. It is one of the most widely used arcade components globally, shipped as OEM equipment in commercial fight sticks from MadCatz, Qanba, and Hori, and installed on service/credit panels in Japanese arcade cabinets. Each unit is a complete assembly: convex plunger, housing, and built-in Sanwa SW-68 microswitch.

2. User Sentiment

The OBSF-24 line consistently earns perfect ratings in the fighting game community. Focus Attack reports a perfect 5-star aggregate, with buyers calling them "the gold standard for fight sticks" and "a necessity for arcade standard." The black (-K) colorway is among the most frequently purchased and is well-stocked at major retailers (Arcade Renovations listed 264 units in stock). Users praise the smooth, quiet feel and extremely short actuation. One known trade-off noted by retailers: the very light activation force means accidental presses are possible during intense sessions — widely accepted as the cost of ultra-responsive feedback.

3. Real-World Applications

The OBSF-24-K is used for start, select, credit, coin, or special-function positions on arcade panels and fight sticks — the 24mm diameter is the standard for non-action buttons, with the 30mm OBSF-30 used for main gameplay inputs. It is the OEM start/select button on Hori, MadCatz, and Qanba fight sticks. In Japanese arcade cabinets, 24mm black buttons appear on test, service, and credit panels. The black colorway is the default neutral choice for most installers and is specified in countless DIY arcade and fight stick build guides.

4. Technical Specifications

• Type: Snap-in pushbutton (OBSF = snap-in flat plunger)
• Mounting Hole Diameter: 24mm
• Compatible Panel Thickness: 2–4mm (0.08–0.16″); sources consistently cite 2–3.9mm / up to 3.7mm for metal or plastic panels
• Plunger Style: Convex (slightly domed), non-clicking; black plunger with black bezel
• Terminals: .110″ / 2.8mm faston (quick-disconnect) spade connectors, 2 terminals
• Microswitch: Sanwa SW-68 (built-in, non-clicking)
  • Operating Position (OP): 0.85mm
  • Total Travel Position (TTP): 2.53mm
  • Operating Force (OF): 55g
  • Required force from rest: 27g
  • Total Travel Force (TTF): 81g
  • Lifespan: 1,000,000 cycles (at 5VDC/10mA)
  • Electrical Rating: DC 12V / 100mA
  • Insulation Resistance: DC 250V / 50MΩ
  • Withstanding Voltage: AC 250V / 1 minute
  • Contact Resistance: 50mΩ max
  • Operating Temperature: −20 to +60°C
• Weight: ~8g
• Color: Black (suffix -K, from Japanese "kuro")
• Complete Assembly: Yes — plunger, housing, microswitch included

5. Ordering & Compatibility

The OBSF-24-K is priced at approximately $2.45–$2.75 USD retail (Paradise Arcade Shop: $2.75; Arcade Shock: $2.45; Arcade Renovations: $2.45) and €2.58 in Europe (Arcade Express). It is compatible with MadCatz FightSticks, Qanba FightSticks, Hori fight sticks, and any custom panel with a 24mm hole in a 2–4mm metal or plastic sheet. Mix-and-Match cap sets are available at Focus Attack for $0.50 savings. The SW-68 switch and 2.8mm faston terminals are shared across the OBSF-24 and OBSF-30 families. The screw-in OBSN-24 is the alternative for panels thicker than ~4mm.

6. Known Issues

The primary concern is the low actuation force (55g, 0.85mm OP), which can cause accidental presses — this is a deliberate design choice for competitive responsiveness. The black colorway is the highest-demand color in the OBSF-24 family and is occasionally listed as out of stock at individual retailers (Focus Attack noted "ships within 1-2 business days when available"). No quality or durability issues specific to the black variant have been reported across available sources. Panels thicker than ~4mm require the OBSN-24 screw-in variant instead.