Name: CISA Astral S 45/40 double cylinder with knob shaft (10A3S2840)
Brand: CISA

CISA 10A3S2840 — Official series illustration, not a photo of this exact size variant; consult model specifications. — Official series illustration, not a photo of this exact size variant; consult model specifications.Image source

10A3S2840 dimension diagram: side B 39.5 mm, side A 44.5 mm, overall body length 84 mm — Our dimension diagram follows the corresponding catalogue row; it is not a product view or machining template; the projecting knob shaft is excluded from body dimension L.

Cylinder dimensions

Dimensions from model documentation
Specifications	Dimensions from model documentation
Dimension A	44.5 mm
Dimension B	39.5 mm
Overall length L	84 mm

Measure both sides from the fixing screw. Check the cylinder profile, cam and version.

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Specifications

Key system: Astral S
Construction: Double cylinder with knob shaft
Nominal size: 45/40
Dimension A: 44.5 mm
Dimension B: 39.5 mm
Overall length L: 84 mm
Coding construction: 10 pin positions: 6 active, 4 passive
Body construction: Brass body with a dual-material anti-snap reinforcing core
Key type: Reversible flat key in special nickel-plated brass
Operating mechanism: Knob-shaft operation

Operation and dimensions of this version

The knob shaft illustrated for 10A3S2840 is on side B; Body B=39.5 mm, key side A=44.5 mm; L=84 mm excludes the projecting knob shaft. The knob is an operating component to verify separately; a shaft configuration does not mean that a complete knob is supplied.

Key system and installation checks

The dual-material reinforcing core in this series uses segmented components along the cylinder length; this is a feature of the body construction. The catalogue lists Code Card; this does not establish key interchangeability with other Astral series.

When selecting, first record nominal size 45/40 for 10A3S2840, then verify the actual 44.5+39.5=84 mm against the drawing. Nominal size is an ordering identifier; adding its two integers does not give the actual overall length.

Limitations

Dimensions are divided at the central reference in the catalogue drawing; a and B do not automatically designate the outside and inside of the door. Installation also requires checking the lock-body cam interface, door thickness and escutcheon thickness.
Catalogue model numbers and dimensions do not establish current stock availability or certification of the complete door; Before purchase, check the actual supplied product's identification plate and the manufacturer's installation documentation.
The catalogue lists series 06353, 06355, 06356 and 06357 knobs as available on request, not as standard equipment for this row.

Sources

CISA 2026 English catalogue, PDF page 99 / printed page 95

Manufacturer documents are provided in their original language.

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