Celmo is a small French effects-pedal maker designed by engineer and musician Celmar Engel, who was previously known for developing software plug-ins for the Creamware DSP platform before turning to hand-built analog hardware. The company's pedals are designed and assembled in France, with each unit individually tested and serial-numbered, and are housed in distinctive brushed-metal enclosures inspired by vintage sardine cans and mid-century industrial design.

The brand's catalog centers on two pedals: the Sardine Can Compressor, an analog optical compressor that pairs smooth sustain with a separately bypassable "soft crunch" drive section and switchable tone-shaping options, and the Pimento Sardine Overdrive, which uses the company's EASE (Enhanced Analog Sag Emulation) circuit to mimic the compression and sag of a cranked tube amp. The Pimento includes a three-position color toggle (Pimento, Lime, and Fat Melon) for shifting the EQ balance of the drive.

Celmo occupies a niche, boutique corner of the French pedal scene, with limited production runs that show up on the secondary market through shops like Reverb. Reviewers at Premier Guitar and Sound On Sound have highlighted the unusual industrial styling and the sag-focused voicing of the overdrive as the brand's distinguishing characteristics.

Celmo has 2 products cataloged on Equipboard, including Compressor Effects Pedals and Overdrive Effects Pedals. Their gear is featured by 1 artist, with the strongest followings in Rock. Notable users include Emmanuel Éthier.