Choosing an impact (pneumatic) heavy-duty socket isn't just a matter of checking a single measurement: drive size, hex opening, 6-point versus double hex geometry, and the standard/long/thin-wall option all need to be considered together. This guide covers the HIS series' complete size chart by drive size and the model selection steps.
| Drive Size | Hex Opening Range | Length Range | Weight Range | Model Count |
|---|---|---|---|---|
| 3/4″ | 17 – 60 mm | 50 – 110 mm | 0.35 – 2.75 kg | 9 models |
| 1″ | 19 – 100 mm | 58 – 150 mm | 0.62 – 6 kg | 9 models |
| 1.1/2″ | 30 – 155 mm | 80 – 210 mm | 1.98 – 23.3 kg | 9 models |
| 2.1/2″ | 50 – 190 mm | 130 – 220 mm | 9.22 – 48 kg | 4 models |
// 735 sizes in 31 size charts across standard, long, and thin-wall (metric) options; 4140 alloy steel at 40–45 HRC hardness, manufactured to UNI-ISO 1174 / DIN 3121.
// PRODUCT PAGE: HIS Series Heavy-Duty Impact Socket — 31 size charts and 735 sizes →
Identify the square drive of your pneumatic/hydraulic wrench (3/4″, 1″, 1.1/2″, or 2.1/2″). This is the first criterion that determines which socket family you'll choose from.
Measure the nut's or bolt head's flat-to-flat width in millimeters and match it to the range in the chart above.
If the nut is rusted/worn or you have standard access, choose 6-point (DRB). If swing clearance is tight and the nut is sound, double hex (CAL, 12-point) is more practical.
If the stud end protrudes below the nut, you need the long (deep) version; if neighboring surfaces sit very close, you need the thin-wall (metric) version. Otherwise standard is sufficient.
| Criterion | DRB · 6-Point (17 Variants) | CAL · Double Hex / 12-Point (14 Variants) |
|---|---|---|
| Contact area | Broader contact with the nut face — lower risk of rounding corners | Smaller contact points — sufficient for light/medium duty |
| Rusted / worn nuts | Recommended — lower risk of slipping and corner wear | Suitable for sound, standard nuts |
| Tight / restricted swing space | Needs a wider swing angle (60°) | Seats at shorter angles (30°) — practical in tight spots |
| Length / wall options | Standard, long, thin-wall (metric) | Standard, long (imperial and metric) |
Pneumatic and hydraulic impact wrenches produce sudden shock loads, repeating hundreds of times per second. Standard chrome sockets are made from chrome-vanadium steel, are thin-walled, and are designed for hand-tool use only — they are not built to withstand this kind of shock loading, and using one on an impact wrench can cause it to crack or shatter suddenly, creating an injury risk. Impact sockets, by contrast, are machined from 4140 alloy steel, heat-treated to 40–45 HRC, and built with a thicker wall matched to the torque requirement to absorb shock loads; they're typically identifiable by a dark (black oxide) finish. In short: wherever a pneumatic or hydraulic impact wrench is used, the dark impact socket should be chosen — never the polished chrome one.
// Adapters step drive size up or down, extensions add reach, universal joints allow angled access, coaxial reduction steps down size without losing the drive axis, and Allen sockets are used for hex-head bolts/screws.
Not sure about your measurement? Send us your hex opening size and your wrench's drive size — Hydro Bard's engineering team will confirm the right model for you at no cost.
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