Implosive consonants are made up of stop consonants (and sometimes some affricates) with a mixed together glottalic ingressive and pulmonic egressive airstream (when the air stream is made by the lungs, ribs, and diaphragm) mechanism. That is, the airstream is used by moving the glottis down in addition to pushing air from the lungs. So, not like the purely glottalic ejective consonants, implosives can be changed by phonation. Contrastive implosives are seen in around 13% of the world's languages.
In the International Phonetic Alphabet, implosives are indicated by changing the top of a letter (voiced stop) with a right-facing hook: ⟨ɓ ɗ ʄ ɠ ʛ⟩.